In the production process，the motor application is extremely widespread，in order to use the electrical machinery well，then carries on the survey in the actual production process using the monolithic integrated circuit to its rotational speed，in order to well for production and life clothing.
In this approch，the engine shaft every time transfers a week，has a quota pulse integer，partially outputs by Sensors electric circuit，After the photoelectricity coupler,，becomes the revolution counter to count the pulse，using 8 Single-Chip Microcomputer AT89S51 to control，and then realizes the counter idea value to correspond the engine shaft the rotational speed value. After CPU this value data processing, demonstrates on the LED numerical code tube，It can easily enter the PID adjust DC Motor Speed with the 4x4 keyboard，Hardware components from Below，this paper uses PID controller，PID algorithm is rectified and make itself perfect due to the flexible software design.
Through to this plan design，let me further deepen the specialized knowledge，has grasped some basic design methods.
Key words：DC Motor；Single-Chip Microcomputer； Sensors；PID control algorithm
