In order to solve the problems of increasing maintenance cost and reducing efficiency caused by improper setting of maintenance cycle for military special vehicles, a method of incomplete preventive maintenance plan for single replacement cycle was proposed. The mixed failure rate function of service age regression factor and failure rate increasing factor is used to describe the change trend of component failure rate. The penalty mechanism is introduced to reduce the maintenance delay caused by accidental factors, and the maintenance cycle is determined with the constraints of reliability and cost-effectiveness ratio of maintenance mode. Taking a certain type of military vehicle as an example, the preventive maintenance cycle is determined by the preset reliability threshold, and the maintenance mode is selected according to the efficiency cost ratio of different preventive maintenance methods, and the maintenance scheme is generated and compared with the traditional scheme. The results show that the method can effectively reduce the failure rate, improve the maintenance efficiency and reduce the waste of maintenance resources.