【Background】The red swamp crayfish (Procambarus clarkii G.) is an invasive aquatic organism to China, and has caused lot damage to the freshwater ecosystems in China. It has few predators, but the native soft-shelled turtle Trionyx sinensis is a potential predator. 【Method】This research aims at discovering the behavioral response of juvenile and subadult crayfishes to the soft-shelled turtle. Experiments were conducted in a "Y"-maze under laboratory conditions. 【Result】Juvenile crayfish, experienced or not, showed a strong aversion to the turtle; subadult crayfish were less sensitive than the juveniles. 【Conclusion and significance】The red swamp crayfish demonstrated avoidance to the soft-shelled turtle. Further tests should be performed to examine the behavioural reactions of this invasive species to its potential predators.