The invention discloses a permanent magnet synchronous motor control system which comprises a main circuit, a discharge protection circuit, a three-phase uncontrollable full-bridge rectification circuit, a driving circuit, a motor, a digital signal processor and a warning circuit which are sequentially connected; the permanent magnet synchronous motor control system also comprises an optical coupler and an interface circuit, wherein the optical coupler is connected between the main circuit and the warning circuit, and the interface circuit is connected with the warning circuit and the digital signal processor; the discharge protection circuit is connected with the digital signal processor through a first isolation amplifying circuit; and the driving circuit is connected with the digital signal processor through a second isolation amplifying circuit. The permanent magnet synchronous motor control system of the invention can reduce the cost, improve the efficiency and save the energy of household appliances and air-conditioning products.