Abstract: This paper introduces a single-chip-microcomputer control system for supersonic-wave fluid-surface-height measurement and the hardware circuit and the software flow chart of the control system. In order to achieve high precision of measurement,the supersonic-wave sensor is set under the container to make supersonic-wave stable. And the integrated circuit 8254 is used in the system, its CLK is provided by an oscillation circuit of high frequency stability. The measurement result shows that the precision of the system reaches centimeter.