Abstract: In order to achieve accurate and non-destructive measurement of the surface topography of an object, a surface topography measurement system using a laser displacement sensor is designed. The system consists of a hardware part and a software part. The hardware part includes a laser displacement sensor, a grating displacement platform, and a PCL833 3-axis quadrature encoder and counter card, the software part includes data acquisition software and MATLAB data processing program. The measured object moves according to a certain path on the grating displacement platform. The data acquisition software stores the coordinate data of the discrete points in the X，Y，Z direction. Finally, the three-dimensional morphology of the measured object is achieved by gaussian filtering using the MATLAB program.

Key words: Laser displacement sensor, Data acquisition, Gaussian filter, Three-dimensional topography