The invention discloses a flux linkage error observation-based acquisition method of a full-order flux linkage observer of an asynchronous motor without a speed sensor and belongs to the field of a speed sensorless vector control full-order flux linkage observer. The problem that the existing speed sensorless vector control system causes low observation accuracy of the full-order flux linkage observer due to larger errors of motor parameters when a motor runs at low speed, and finally, the running stability of the system is poor is solved. A full-order flux linkage observer error feedback matrix coefficient is obtained according to the following rules, namely, the pole real part of the observer is smaller than the pole real part of an asynchronous motor, the real parts are both negative numbers, the zero pole real parts of an estimation rotation speed and a transfer function are both negative numbers, the error between an estimation flux linkage and a real flux linkage is utilized, when the motor runs at low speed, the equivalence of the system is a current model, and when the motor runs at high speed, the equivalence of the system is a voltage model. The rotor flux linkage phase position error coefficient ilambda is utilized and the rotor flux linkage amplitude error coefficient k is introduced, so that the estimation rotating speed precision is increased. The flux linkage error observation-based acquisition method of the full-order flux linkage observer of the asynchronous motor without the speed sensor is particularly used in the field of speed sensorless vector control.