Abstract: The layout of on-board equipment is an important link in the design of rolling stock. The optimization of the equipment layout plays an important role in ensuring the safe operation of rolling stock. Considering the constraints of equipment interference and module boundary etc., an equipment layout optimization of rolling stock mathematical model was established that minimized the distance between the total gravity center of equipment and center of the rolling stock. According to the characteristics of equipment layout optimization of the rolling stock, an equipment layout optimization of rolling stock mathematical model based on particle swarm optimization(PSO) algorithm was designed. Using the linearly decreasing inertia weight strategy, the PSO algorithm was effectively guided to converge to the global optimal solution by improving the penalty factor. Finally, this paper presented an example of the optimization design of on-board equipment layout of a track construction vehicle and showed that this method could effectively solve the problem of equipment layout optimization of rolling stock.