During World War II he took over the command of 17th Army Group.
He was also the vice-commander of the 8th War Zone.

During the early 1930s Edgar Snow in his book Red Star Over China said that the Communist media (who were enemies of Ma Hongkui) claimed that Ma received some weapons from Japan when he was fighting the Communists, and met visiting delegations, but after Japan's invasion of China in 1937 he fought against Japan, supporting the imam Hu Songshan in spreading anti-Japanese propaganda, and sending limited numbers of troops to his cousin Ma Hongbin to fight the Japanese.
According to Snow, the Communists claimed Ma had allowed a Japanese military airfield and some personnel in Ningxia, but the airfield was not there after the start of the Sino-Japanese War in 1937, reaffirming his allegiance to China.

When the Japanese asked Gen. Ma Hongkui to defect and become head of a Muslim puppet state under the Japanese, Ma responded through Zhou Baihuang, the Ningxia Secretary of the Nationalist Party, to remind Japanese military chief of staff Gen. Itagaki Seishiro that many of Ma's relatives fought and died in battle against Eight-Nation Alliance forces during the Battle of Peking (1900), including his uncle Ma Fulu, and that Japanese troops made up the majority of the Alliance forces, so there would be no cooperation with the Japanese.
In response, Ningxia was bombarded by Japanese warplanes.

Ma Hongkui maintained a sharp watch against Japan during the war.
He seized the city of Dingyuanying in Suiyuan and arrested Mongol prince Darijaya (Wade Giles : Ta Wang) in 1938 because a Japanese officer of the Kwantung Army, Doihara Kenji, visited the prince.
Darijaya was exiled to Lanzhou until 1944.

In 1940 Ma Hongkui's Muslim troops took part in the Battle of West Suiyuan against Japan and their Mongol puppet state Mengjiang.
Because of fierce resistance by Ma Hongkui and Ma Bufang's Muslim cavalry, the Japanese never reached Lanzhou during the war.

Ma Hongkui attacked the Inner Mongol Prince Darijaya and defeated the Mongol banner militia under his command in March 1938, accusing the Prince of collaborating with Japan, arresting him and saying he was "annihilating and extirpating pro-Japanese elements in Alashaa Banner."
Ethnic Mongolian guerilla units were created by the Kuomintang Nationalists to fight against the Japanese during the war in the late 30s and early 40s.
These Mongol militias were created by the Ejine and Alashaa based commissioner's offices created by the Kuomintang.
Prince Demchugdongrob's Mongols were targeted by Kuomintang Mongols to defect to the Republic of China.
The Nationalists recruited 1,700 ethnic minority fighters in Inner Mongolia and created war zones in the Tumet Banner, Ulanchab League, and Ordos Yekejuu League.
During World War II he took over the command of 17th Army Group. He was also the vice-commander of the 8th War Zone.
During the early 1930s Edgar Snow in his book Red Star Over China said that the Communist media (who were enemies of Ma Hongkui) claimed that Ma received some weapons from Japan when he was fighting the Communists, and met visiting delegations, but after Japan's invasion of China in 1937 he fought against Japan, supporting the imam Hu Songshan in spreading anti-Japanese propaganda, and sending limited numbers of troops to his cousin Ma Hongbin to fight the Japanese. According to Snow, the Communists claimed Ma had allowed a Japanese military airfield and some personnel in Ningxia, but the airfield was not there after the start of the Sino-Japanese War in 1937, reaffirming his allegiance to China.
When the Japanese asked Gen. Ma Hongkui to defect and become head of a Muslim puppet state under the Japanese, Ma responded through Zhou Baihuang, the Ningxia Secretary of the Nationalist Party, to remind Japanese military chief of staff Gen. Itagaki Seishiro that many of Ma's relatives fought and died in battle against Eight-Nation Alliance forces during the Battle of Peking (1900), including his uncle Ma Fulu, and that Japanese troops made up the majority of the Alliance forces, so there would be no cooperation with the Japanese. In response, Ningxia was bombarded by Japanese warplanes.
Ma Hongkui maintained a sharp watch against Japan during the war. He seized the city of Dingyuanying in Suiyuan and arrested Mongol prince Darijaya (Wade Giles : Ta Wang) in 1938 because a Japanese officer of the Kwantung Army, Doihara Kenji, visited the prince. Darijaya was exiled to Lanzhou until 1944.
In 1940 Ma Hongkui's Muslim troops took part in the Battle of West Suiyuan against Japan and their Mongol puppet state Mengjiang. Because of fierce resistance by Ma Hongkui and Ma Bufang's Muslim cavalry, the Japanese never reached Lanzhou during the war.
Ma Hongkui attacked the Inner Mongol Prince Darijaya and defeated the Mongol banner militia under his command in March 1938, accusing the Prince of collaborating with Japan, arresting him and saying he was "annihilating and extirpating pro-Japanese elements in Alashaa Banner." Ethnic Mongolian guerilla units were created by the Kuomintang Nationalists to fight against the Japanese during the war in the late 30s and early 40s. These Mongol militias were created by the Ejine and Alashaa based commissioner's offices created by the Kuomintang. Prince Demchugdongrob's Mongols were targeted by Kuomintang Mongols to defect to the Republic of China. The Nationalists recruited 1,700 ethnic minority fighters in Inner Mongolia and created war zones in the Tumet Banner, Ulanchab League, and Ordos Yekejuu League.
Ma Hongkui