In order to improve the control performance of the permanent magnet synchronous motor speed control system, combined with sliding mode control and fractional calculus theory, a fractional order integral sliding mode speed controller and an improved sliding mode observer were designed. For the speed controller, the design of a new reaching law based on inverse hyperbolic sine function, which weakened the system chattering effectively, the fractional order control provided the system with more degree of freedom and it could reduce the chattering more and enhance the robustness of the system. Aiming at the observer, a new sliding mode observer based on the new reaching law of fal function was designed to obtain the back EMF value, and then utilized the FOPLL to extract the rotational speed information in the back EMF. The highprecision rotor position and velocity estimation value could be obtained. The simulation experiments verified the feasibility and validity of the proposed method.