Abstract: The effects of target type and cognitive flexibility on task performance were investigated by inter-subject experiment design. The results showed that the main effect of target type was significant. The task performance of the subjects who set the challenging performance target was significantly higher than that of the subjects who set the learning target. The main effect of cognitive flexibility was significant, and the subjects with higher cognitive flexibility had higher task performance. There were a significant interaction between target type and cognitive flexibility. Subjects with high cognitive flexibility had higher task performance when setting performance target. The research results show that in complex problem solving, task target should be set reasonably according to one's mastery of current task-related knowledge or skills and one's cognitive flexibility.