Abstract: 【Objective】Explored the reasons for the slow growth of Macrobrachium rosenbergii from the perspective of energy metabolism，and provide a reference for analyzing and solving the problem of slow growth of M.rosenbergii. 【Method】siRNA was used to inhibit the expression of COX2 gene in hepatopancreas and muscle of M. rosenbergii，and the changes of gene expression and enzyme activity of mitochondrial respiratory chain and ATP content in hepatopancreas and muscle of M. rosenbergii were analyzed. The effect on growth of M. rosenbergii was analyzed by consistently inhibiting gene expression of COX2.【Result】siRNA could inhibit the expression of COX2 gene of M. rosenbergii. Within a certain range of concentration，the inhibition became more obvious with the increase of siRNA concentration，and the inhibition was not obvious beyond a certain range of concentration. siRNA at 2.0 μg/g showed the best inhibitory effect compared with 0.8，1.5 and 3.0 μg/g siRNA. After siRNA injection，COX2 gene expression was down-regulated in hepatopancreas and muscle of M. rosenbergii，as well as the expression of ND1 and ATP6 genes，COX，ATP synthase，CCR and ND enzyme activities were significantly decreased（P<0.05，the same below），and content of ATP was decreased in hepatopancreas and muscle. Continuous injection of siRNA could continuously inhibit the expression of COX2 gene in hepatopanax and muscle of M. rosenbergii. With the increase of the number of siRNA injection，the inhibition time of COX2 gene expression also increased. In the hepatopancreas and muscle of shrimps injected 2.0 μg/g siRNA for 4 times，the expression of COX2、ND1 and ATP6 genes were continuously down-regulated for the longest time，and the activities of COX，ATP synthase，CCR and ND enzymes were significantly lower than control groups for a long time，and the content of ATP was also significantly lower than control groups. The body length and weight gain of M. rosenbergii decreased with the increase of inhibition time of COX2 gene expression in hepatopancreas and muscle. After 28 d of culture，the net weight gain of shrimp injected with siRNA one time and four times was 0.59 and 0.34 g.【Conclusion】When the gene expression and enzyme activity of enzymes involve in ATP synthesis are inhibited for a long time，it will inhibit the growth of M. rosenbergii.