A speed estimation method, which can estimate the rotor resistance, was proposed for induction motor, whose rotor resistance is unknown. In this scheme, the stator resistance was supposed to be known, therefore the improved voltage model was used to estimate the rotor flux. From the stationary frame model of induction motor, two expressions of rotor speed and rotor resistance were deduced. Under the condition that the rotor flux is known, the two expressions are taken as two binary simple equations. Solving the two equations, we can get the expressions of the unknown rotor speed and rotor resistance. The validation requirements of the two expressions were analyzed. The speed sensorless control scheme was proposed for induction motors. The simulation results indicate that the proposed scheme can estimate the rotor speed and the rotor resistance accurately.