The invention relates to a stability control main engine testing method and system. The stability control testing method comprises the steps of simulating a plurality of stability control slave engines through a tester to acquire power state data of the home station, and sending the power state data to a stability control main engine. The stability control main engine executes a strategy accordingto the power state data of the home station and outputs a main engine message. The tester simulates a plurality of opposite factory stations to receive the main engine message and transmits the messages to an upper computer. The upper computer tests the function of the stability control main engine according to the main engine message. The stability control main engine testing method improves testing efficiency and saves testing cost.