the combined waterwheel oxygen - increasing machine pertains to the area of life - saving and facilitation equipment in aquaculture development . the existing waterwheel oxygen - increasing machine is a floating body with brackets integrally connected , inconvenient for assembly and disassembly and for general use . the present invention comprises of floating bodies , a power device , a reduction gearbox and impellers , wherein the power device is connected to a reduction gearbox , which then drives said impellers via an output shaft . the floating bodies are hollow , closed , bodies including longitudinal floating bodies and transversal floating body connected vertically with each other , wherein one end of the longitudinal floating bodies are connected to transversal floating body . the floating bodies bear an output shaft . the impellers are located in the midst of the area surrounded by the longitudinal floating bodies and the transversal floating body . moreover , said impellers are overlapping impellers connected in a series by a plurality of single impeller bodies . the advantages of the invention lie in the adjustable number of floating bodies and impellers for different needs according to the actual oxygen - increasing power , flexible assembly and installation , convenient assembly and disassembly , good general property use and wide applicable scopes . in addition , light weight and fine floating properties as well as a low manufacturing cost for plastic materials are used .