A method for controlling the start-up phase of a sensorless permanent magnet synchronous motor, the method including: 1) according to the formula T=K×Iq where T is a torque, K is a coefficient, and Iq is a current on a q-axis of a coordinate system of a motor mathematical model, based on a maximum output torque Tmax of a motor, calculating a maximum current Iq_max on the q-axis, setting the maximum current Iq_max as an upper limit of current on the q-axis, and controlling the motor to run in an open-loop control mode; and 2) when an actual running speed V of the motor reaches a first target speed V_ref1, reducing the maximum current Iq_max to a target current Iq0 on the q-axis corresponding to a target torque T0 set by users, and controlling the motor to run in a closed-loop control mode under the first target speed V_ref1.