The expected torque tracking control problem of induction motor based on passivity principle is analyzed in case of arbitrary unknown time varying load torque and rotor resistance. The mathematical model of induction motor in Euler-Lagrange (E-L) equation is built. The controller, the expected orbit, the expected toque, the rotor resistance estimator, the load torque estimator and the rotor state observer are designed. Through these processes, it is theoretically proved that the expected torque and speed can be tracked asymptotically and the load torque and rotor resistance can be estimated rapidly. The MATLAB/Simulink simulation results also show the correctness, validity and excellent performance of the proposed method.