This paper proposes an adaptive speed and position tracking control of an induction motor subject to unknown load torque via strictly positive real (SPR) analysis. The controller is developed under a special nonlinear coordinate transform such that either speed or position control objective can be fulfilled. The underlying design concepts are to endow the close-loop system while under lack of knowledge of some key system parameters, such as the rotor resistance, motor inertia and motor damping coefficient. The proposed control scheme comes along with a thorough proof derived based on Lyapunov stability theory. The experimental results are also given to validate the effectiveness of the presented control scheme.