Abstract: RNA interference is a powerful tool for investigating gene function which has been used extensively in model organisms such as Caenorhabditis elegans and has been adapted as a high-throughput screening method to identify genes. However， recent research indicates that the application of RNAi to animal parasitic nematodes has some problems. For example, the variability of RNAi to different parasitic nematodes or the same nematode in differert stages is great. Reasons to explain why RNAi does not work well in animal parasitic nematodes include： ① the efficacy of RNAi delivery methods in different nematodes is extremely variable；② RNAi mechanism has been applied to related nematodes and most of them are gene functional defect；③ different lifestyles of nematodes may influence on the efficacy of RNAi. If we can find out the methods which can solve these questions， there are still application prospects for using RNAi in parasitic nematodes with improved RNAi effect.

Key words: RNA interference, Animal, Nematode, Limitation