Based on the sensorless control technology of permanent magnet synchronous motor (PMSM), a constant power control algorithm for the PMSM of household electrical appliances is put forward. In the proposed method, the calculated motor power is adjusted with Kalman filtering to achieve high precision, and a power control loop with power tracking functionality is designed, so as to adaptively realize the maximum power control of the PMSM. The design of controller and motor drive is implemented. Test results show that, with the proposed method, the washing machine motor can keep working at the maximum power status.