Abstract: The intrinsic increasing rate of Moina mongolica Daddy,a euryhaline cladocera species isolated from inland brackish lakes of northwestern China,was studied at 20℃～33℃, 5～40ppt,respectively.The results showed that its intrinsic increasing rate(r_m) increased with increasing temperature from 20℃～30℃,and sharply dropped with further increasing temperature up to 33℃.The r_m of M.mongolica was relatively high at low salinity,the highest at 10ppt,but no significant difference at 20～40ppt.Therefore,25℃～30℃, 10ppt could be optimal for the development of M.mongolica population,and its increasing potential would not be affected significantly by rearing this cladocera species in seawater for a long period.