The hydraulic drive system of shield hauler in the underground coal mine production has the disadvantages of poor working conditions, large fault fuzziness and randomness, high maintenance cost, and difficult to the road test. In order to solve this problem, according to the mechanical structure and working principle of A4VG type piston pump, the cosimulation model of the system was established by the parametric modeling method, and the pressure and flow characteristics of the pump and the operation characteristics of its control circuit were analyzed. Then the test platform of the system is built to test the performance of the piston pump and its control circuit. The results show that the method of combination of experiment and numerical simulation could effectively reflect the maintenance results of the pump controlled circuit, which greatly improves the maintenance efficiency and reduces the cost.