To solve the laboratory test problem of dynamic positioning performance of GNSS/INS integrated navigation terminal, this paper proposes a two-step method of GNSS / INS joint simulation based on the turntable inertial simulation test and satellite navigation simulation test technology. First the characteristic error model through the physical measurement of inertial sensor was obtained, and then the model was drived by using the carrier initial conditions and track data in the test scene to generate the analog output data stream of inertial sensor, and finally the GNSS signal simulation was synchronized to realize the process of GNSS / INS joint simulation. After compared with the field measurement, the simulation test results prove that the accuracy of the test data obtained by this method meets the expected indicators, the results are reliable, and the cost is lower and the efficiency is higher than other traditional test methods.