A multitorque load system due to the load test only at a fixed speed in traditional variable frequency motor experiment system was studied. Based on the character of induction machine, the multitorque load system set up mathematical model and calculate to regulate the service voltage and frequency swiftly. Hence many kinds of dynamic load were simulated. The operating principle was illustrated, simulating methods and analysis of the system, which attested to reliability of the load system in meeting the demand for the experiment.