Abstract: The method of diving and recovering under great pitch degree without power is very important to an Autonomous Underwater Vehicle. However, it can’t meet the requirement for the control of the diving and recovering position range, and of the heading.This difficult problem can be solved by mounting winglets on the stabilizing wing. In this paper, we describe the influence of winglets on the diving and recovering locus of Autonomous Underwater Vehicle without power, and analyze it qualitatively with the motion equations and the deep sea test results of the Autonomous Underwater Vehicle “CR-01” (dive at a depth of 6000m). The results provide a theoretical base for getting the best winglet through testing.