The principle of stator-flux-oriented indirect stator-quantities control of asynchronous motor is analyzed, and the space voltage vector is calculated according to the phase increment and range increment of stator flux. A full order flux observer of induction motor is constructed with stator flux and rotor flux as state variables. The control method is simulated with Matlab, the result shows that the indirect stator-quantities control system based on the full order flux state observer has strong robustness, and also has good dynamic and steady response performance.