The equal-cycle preventive maintenance strategy is a common maintenance strategy, which has the characteristics of simple implementation. Aiming at the problem that the optimization modeling granularity of the The equal-cycle preventive maintenance strategy is a common maintenance strategy, which has the characteristics of simple implementation. Aiming at the problem that the optimization modeling granularity of the current equal-cycle preventive maintenance strategy is too large, and fault difference (the difference of preventive maintenance effects on different failures) is rarely considered, this paper takes the meta-action unit as the research object, divides unit failures into damage failures and intrinsic fatigue failures, and considers the difference of preventive maintenance effects on these two types of failures. The hybrid failure rate model is used to describe the imperfect maintenance effect, and an optimization model for equal-cycle imperfect preventive maintenance strategy is developed. Finally, numerical analysis is performed to verify the effectiveness of the proposed model and to analyze the influence of different maintenance costs on the optimal maintenance cost rate and the optimal maintenance strategy. It was shown that the maintenance cost rate of the meta-action unit would be underestimated without accounting for the difference of preventive maintenance effects; the different types of maintenance costs and the proportion of failure types have a significant impact on the formulation of the optimal maintenance strategy for the meta-action unit.