Abstract: The present experiment simulated the temperature fluctuation during the culture period of grass carp(Ctenopharyngodon idellus)to examine the effects of the changes in temperature on the budgets of C,N and P nutrients.Grass carp were cultured at temperatures of 15,18,24 and 30 ℃ and the processes of C,N and P budgets were examined.The results showed that C,N,P nutrient budgets of grass carp were significantly different between the 4 temperature groups(P<0.05).The feed uptake rate,nitrogen excretion rate,phosphorus excretion rate and fecal production rate of grass carp were 3.405 7,7.533 4,0.000 8 and 0.601 3 mg/h at 15 ℃,respectively,which were significantly lower than other groups(P<0.05),and reached the maximum values at 24 ℃,which were 10.442 0,18.995 6,0.001 7 and 1.647 0 mg/h,respectively.The oxygen consumption rate(OR)increased with increasing temperatures(T)following the formula OR=0.005 9×T^1.2532(R²=0.84).The scope for growth(SFG)of C,N and P of grass carp were 1.064 9,0.126 4 and 0.018 8 mg/h at 15 ℃,respectively,which were significantly lower than other groups(P<0.05),and reached the maximum values at 24 ℃,which were 3.402 8,0.397 1 and 0.071 8 mg/h,respectively.The absorption efficiencies of C,N and P of grass carp were 81.38%,83.05% and 80.30% at 15 ℃,respectively,which were significantly lower than the 24 ℃ and 30 ℃ groups(P<0.05).