To investigate the influence of transmission system speed ratio of vehicle equipped with 2-speed AMT on vehicle’s performance, this paper, taking a pure electric logistics vehicle as an research object, matched and designed the vehicle’s driving motor, battery pack and transmission system speed ratio according to the vehicle’s basic parameters. The vehicle model was established based on the AVL_CRUISE simulation platform, the rationality of matching parameters was verified by simulation, and Particle Swarm Optimization (PSO) algorithm was selected to improve the vehicle’s power and economy, and the speed ratio of transmission system matching two-gear AMT was optimized. The simulation results show that the 0-100 acceleration time of the pure electric logistics vehicle is shortened by 2.31 s after optimization, the energy consumption of the vehicle is reduced by 3.14% under single NEDC cycle condition, and the power performance and economy of the vehicle are obviously improved.