Abstract: Objective：Establishing an back incision pain rat model to observe the subjective reaction of rats to acetaminophen with conditioned place preference（CPP）experiment. Methods：Made a skin cut then suture at the right lower back of rat，then used acetaminophen 100 mg/kg and observed CPP values for 4 times at 12 hours' interval；comparing the difference between preCPP and postCPP. Results：The postCPP values of incision pain rats were significantly increased compared with preCPP（P < 0. 05），while those of sham rats and control rats were not when compared with their preCPP. Conclusion：This rat back incision pain model is suitable for observing the reward effects of pain relieve agents with CPP experiment，and will be helpful to assess the subjective unpleasantness of animals to pain.