Digital video camcorder is a kind of mechanical and electrical product that is easy to make misoperation. Chose green hand users as subjects.Then applied experiment method to study their misoperation manner in using Sangsumg VP－101 digital video camcorder. According to industrial design psychology and ergonomics theory , analysed experimental result. Firstly, through F testing of psychology statistics method, found that the major effective reason of misoperation was task difference which was relevant to interface and interacting means design factors, and individual difference of each subject had little effect on misoperation. Secondly, in terms of analysis on the relevance of interacting means design details and misoperation manner, found rational design reasons of misoperation. They were mismatching attribute of perception, mismatching attribute of touching size, lack of visuality. Thirdly, On the basis of statistics on subjects mood research, found that nervous and whiny mood were irrational factors affecting misoperation. The conclusion could be summarized as the three results mentioned above. Specific to this conclusion, discussed methods to deduce misoperation by building user task model, user mental model and green hand user mood model.