Efficient maintenance management of devices is fundamental to ensuring supply reliability of natural gas pipeline system. A joint optimization model of preventive maintenance and spare parts ordering for the gas compressor in pipeline system based on supply reliability is developed aiming to maximize system gas supply reliability and minimize maintenance costs. The model consists of three parts: calculation of the maximum gas supply capacity, modeling of the joint optimization problem and using a genetic algorithm to find the optimal solution. The effectiveness of the proposed method is validated on a European gas pipeline network. The results show that the proposed joint optimization strategy outperforms others in identifying optimal maintenance strategies.