Abstract: Three species of rodents were studied on metabolism and thermoregulation, They arc mandarin vole (Microtus mandarinus ) . fossorial! ratlike hamster ( Cricclu lus triton), burrowing; buff-breasted rat ( Rattus flavipccius ), above ground.Their body temperature ( T_b ), oxygen consumption ( ml0₂/g.h ) and body weight ( W ) were measured at different ambient temperatures ( T_a ), 5°,10°,20°,25°,30°, 35℃.The differences of oxygen consumption in the tiree spcies as due to the differences of their body weights were adjusted with the method analysis of covariance, and the mean minimum oxygen consumption of each species in resting slate was taken as the basal metabolic rate ( BMR ) : in mandarin vole, the BMR at an ambient temperature of 20℃, being 3.07 m10₂/g.h, and rat-like hamster and buff-breasted rat at 25℃, T_abeing 2.31 m10₂/g.h and 2.62 m10₂/g.h respectively.( table 2 ).