A self-adaptive control and protecting system of an asynchronous motor is characterized by comprising a system core control module, a power module, a power factor module, an analog signal acquisition module, a thyristor and a data transmission module. The power module, the power factor module, the analog signal acquisition module, the thyristor and the data transmission module are connected with the system core control module. The system core control module is composed of a single-chip computer in S3C44B0 series, a synchronous signal detecting module and a trigger circuit module, and the trigger circuit module consists of two secondary winding pulse transformers. The analog signal acquisition module is composed of a voltage signal acquisition module and a current signal acquisition module. Work efficiency of the asynchronous motor is improved, power of the asynchronous motor can be automatically off and the asynchronous motor is protected on the condition of overloaded, unbalance among three phases and phase default, and thereby the service life of the asynchronous motor is prolonged. Meanwhile, a soft start function is added, and the problem of waste of energy caused by overload of current is solved when the asynchronous motor is started, and the like.