The invention relates to an automatic switching action method for action of a self-adaptive security system. The method comprises the steps of 1, determining an automatic switching starting condition; 2, determining an automatic switching opening condition; and 3, executing automatic switching action. By the automatic switching action method, the defect of misoperation probably caused by removal of a main supply power incoming line by a current automatic switching device during action of the security system is overcome, meanwhile, the problem that the automatic switching device rejects to start when the main supply power incoming line exits running due to a short-circuit fault is also effectively solved, and the action correctness of the automatic switching device is improved.