The holotype specimen (catalogued as HGM 41HIII−0201 in Henan Geological Museum, Zhengzhou) was discovered near Songgou Village, which is in the northeast region of Xixia County, in Henan Province of central China.
This area of the Xixia Basin exposes the Majiacun Formation.
In 2010, the specimen was described as the new genus and species Xixiasaurus henanensis by the palaeontologist Lü Junchang and colleagues.
The generic name refers to Xixia County coupled with saurus, meaning "lizard", while the specific name refers to Henan Province.
The full name can be translated as "Henan Xixia lizard".
Remains of troodontids are very rare compared to those of other small theropod dinosaurs (only thirteen troodontid taxa were known at the time Xixiasaurus was named), and have mainly been found in Asia.

The holotype specimen is the only known Xixiasaurus fossil, and consists of an almost complete skull except for the hindmost portion, as well as a partial right forelimb.
The connection between the frontal (forehead bone) and nasal (bone running at the upper length of the snout) bones is displaced, and part of the braincase is missing.
Most of the snout is preserved, with the dentition of the right side being well-preserved.
Only the front part of the left dentary bone (tooth-bearing bone of the mandible) and some of its broken teeth are preserved.
Though several teeth are missing from both jaws, their original number can be determined in the upper jaw, since their sockets there are preserved.
The forelimb (of which all preserved parts are articulated) consists of the middle part of the radius and ulna (bones of the lower arm), the extremity of the second and third metacarpals (hand bones), the complete first finger, and the first phalanx bone of the second finger.
In 2014, the palaeontologist Takanobu Tsuihiji and colleagues stated that a bone Lü and colleagues had originally identified as the vomer (part of the palate) of Xixiasaurus was instead part of the premaxillae or maxillae (the main bones of the upper jaw), based on comparison with the vomer of the more complete troodontid Gobivenator.
The holotype specimen (catalogued as HGM 41HIII−0201 in Henan Geological Museum, Zhengzhou) was discovered near Songgou Village, which is in the northeast region of Xixia County, in Henan Province of central China. This area of the Xixia Basin exposes the Majiacun Formation. In 2010, the specimen was described as the new genus and species Xixiasaurus henanensis by the palaeontologist Lü Junchang and colleagues. The generic name refers to Xixia County coupled with saurus, meaning "lizard", while the specific name refers to Henan Province. The full name can be translated as "Henan Xixia lizard". Remains of troodontids are very rare compared to those of other small theropod dinosaurs (only thirteen troodontid taxa were known at the time Xixiasaurus was named), and have mainly been found in Asia.
The holotype specimen is the only known Xixiasaurus fossil, and consists of an almost complete skull except for the hindmost portion, as well as a partial right forelimb. The connection between the frontal (forehead bone) and nasal (bone running at the upper length of the snout) bones is displaced, and part of the braincase is missing. Most of the snout is preserved, with the dentition of the right side being well-preserved. Only the front part of the left dentary bone (tooth-bearing bone of the mandible) and some of its broken teeth are preserved. Though several teeth are missing from both jaws, their original number can be determined in the upper jaw, since their sockets there are preserved. The forelimb (of which all preserved parts are articulated) consists of the middle part of the radius and ulna (bones of the lower arm), the extremity of the second and third metacarpals (hand bones), the complete first finger, and the first phalanx bone of the second finger. In 2014, the palaeontologist Takanobu Tsuihiji and colleagues stated that a bone Lü and colleagues had originally identified as the vomer (part of the palate) of Xixiasaurus was instead part of the premaxillae or maxillae (the main bones of the upper jaw), based on comparison with the vomer of the more complete troodontid Gobivenator.
Xixiasaurus