A electro-control system for laser phototype-setter using singl-chip micro-computer MCS51 was designed and realized. A new concept of primary and secondary scanning control was formed. In primary scanning system the construction was simplified without-using optical encoder and the reliability was raised. In secondary scanning system the fine control of step-motor was used for raising the accuracy of step-motor. The scanning coutrol of laser phototype-setter with different resolution was estalished by the help of single-chip microcompter.