Abstract: In order to ensure the good operation performance of generator car, we need to test the generator car regularly. The output load carrying capacity of the generator car can be effectively detected by using analog resistive and inductive loads.During the load test of the generator car, we found that there was a serious imbalance of current distribution between the in-phase output cables of the generator car. By changing the type and capacity of generator car, cable laying method, the method of connection between the cable and generator car, we finally find that the cable current carrying capacity is influenced by the cable laying method. And we put forward relevant measures to improve the uneven distribution of generator car output cables.