Since the train runs fast，it is necessary to build a long enough bridge and to adopt a sufficiently refined vehicle-track-bridge coupling mode in real-time hybrid testing of high-speed railway system． Therefore，high accuracy and efficiency of numerical computation is essential． At the same time，the real-time hybrid testing requires high instantaneity，and each step needs to be completed in a short time，which further increases the difficulty of the problem． To this end，a new computation method，named the moving load integration method，was proposed． The data needed for the numerical substructure computation of the bridge was stored before the testing． In the actual computation，the corresponding data of each time step was extracted and computed to obtain the displacement response of the current time step． The method was extended to the local nonlinear condition by means of the elastoplastic numerical substructure method，and then the feasibility and reliability of the method were systematically verified by the real-time hybrid testing of the scaled-down high speed railway shaking table．