Debugging is the most difficult part of programming for novices. Through comparative experiments, this paper compares the differences between novices and the experts in the debugging process from the perspective of the frequency of each debugging skill behavior and the connection of each behavior. The study find that there is a difference in the behavior of novices and experts in generating hypotheses, and the behavior transition of novices and experts also changed according to the difficulty of the task. [Author name omitted due to Chinese characters.]