With the internationalization of manufacturing industry in our country today, how to ensure the high reliability of production equipment and minimize the cost of equipment maintenance has become an important issue for the survival and development of enterprises. Flexible formulation of the corresponding equipment update strategy is of great significance for reducing the operating costs of enterprises, improving the labor productivity of enterprises and even enhancing the competitiveness of the industry. This article research on maintenance method and replacement policy of engine cylinder automatic production line equipment of a car factory uses failure statistics and analysis method to process related equipment maintenance data and obtain the failure model. On this basis, the equivalent cycle model for series system of multiple devices is established. The equivalent cycle model is established on the finite interval [0,T]. In the model, reliability and maintenance costs are respectively as the objective function, and the other one as the constraints. Then a variable cycle preventive maintenance model is established, in which the average cost rate is as the objective function, and reliability of each preventive interval as the constraints. These preventive maintenance decision models can provide a quantitative basis for decision making in maintenance activities. And , according to the failure frequency and maintenance costs of each engine cylinder production line equipment, this article identify the key equipments for maintenance. Using these key equipments as study object, make an empirical study for these preventive maintenance decision models. Finally, based on game theory, replacement policy for the engine cylinder production line equipment is researched. This replacement model provides a more systematic decision-making way for equipment replacement analysis. Providing a new thinking method, it can be a reference available for maintenance staff.