Abstract: This paper analyzes the interference field which causes the false action of active electromagnetic fuze in torpedo, and identifies electromagnetic incompatibility inside torpedo and sailing vibration of torpedo as the key sources. Therefore, the requirements of counter-countermeasure design and safety design are put forward to optimize the anti-false action design. Test results show that the improved designs can effectively reduce the probability of false action and enhance the reliability of torpedo fuze action. Moreover,a method for calculating probability of false action is presented to examine anti-interference design of fuze.