Aiming at the problem of multicylinder synchronous motion of hydraulic system of large hydraulic machines, a solution to achieve the precision synchronous control by using a hydraulic numerical controller (HNC) was put forward. The control principle, system hardware and software structure of the hydraulic test platform were elaborated. The normal operation of the hydraulic test platform was realized by this system, and the tested data was analyzed. The test results indicate that the application of HNC in the hydraulic control system has very high precision. 