Abstract: There are 3 juvenile instars and 6 adult instars of Moina irrasa (Cladocera)at 25 ± 1℃. The average life span is 167.7h, the average number of egg production per adult is 117, the mean maximum body length is 1.75 mm, and the intrinsic growth rate is 1.358 / d. There are 3 juvenile instars and 7 adult insane at 30±1℃. The average life span is 121.0h, the average number of egg production per adult is 106.6,the mean maximum body length is 1.71 mm. The intrinsic growth rate is 1.650/d.The growth of length and weight the instantaneous weight increment rate and instantaneous length relative increment rate equations of M. irrasa at 25 ±1℃ and 30 ±1℃ are as following in which the length (L) unite is mm, the weight (wet weight,w) is mg, and the bine (t) is the day.25±1℃, Lt = 1.8801 - e-0.3185(t+1.8620) W = 0.37281 - e-0.3185(t+1.8620)2.3814 dW/dt = 0.15625·e -0.3185t(1-0.55264e-0.3185t)1.3814 dL/Ldt = 0.3185/e0.3185(t+ 1.8620) -1 30 ±1℃, Lt = 1.7081-e-0.7428(t+0.7733) W = 0.29661-e-0.7428(t+0.7733)2.3814 dW/dt = 0.29542·e-0.7428t(1-0.56304e-0.7428t)1,3814 dL/Let = 0.7428/e0.7428(t+0.7733)-1At the begining of life span the length. weight and their growth rates at 30 ±1℃ are bigger than those at 25±1℃. But after mid life span that the length, weight and theirs growth rates at 25 ±1℃ are bigger than that at 30 ±1℃ instead. The instantaneous weight increment rates at 25±1℃ and 30±1℃ have a maximum value when t = 0.862d and 0.395d respectively. When t = 0 or just be born, the instantaneous length relative increment the at 2 temperatures each has a maximum value.