This paper proposes an Hinfin state feedback controller is used in the speed control for a micro permanent magnet synchronous motor. In addition, the genetic algorithms are used to determine the weighting functions of the Hinfin controller. An optical encoder with 100 pulses/revolution is used to achieve the rotor position of micro permanent magnet synchronous motor, which has fast response and good load disturbance rejection capability. The digital signal processor TMS320LF2407 is used as the control center to execute the estimation and control algorithms. Experimental results validate the theoretical analysis to show the correctness and feasibility of this dissertation.