For better machining and electrical characteristic, the complex surfaces topography of some delicate machining tools and electronic components should be acquired precisely, including shape and size of microstructure on surface of engineering material or precision component from microscopic view, and relationship between microstructures from macroscopic viewpoint, such as spaces, distribution and so on. This so called multiscale measurement has been greatly focusing by experts and scholars from home and abroad. People researched this novel measurement in several ways: (1) putting different sensors together, which had different resolution and measuring range; (2) applying software technology, include wavelet theory, fractal theory and image mosaicing technology, to solve this multi-scale measurement problem. However, it’s difficult to cooperate with many different sensors in multi-sensors measurement technology, and mathematical modeling is very complicated in software technology. This paper used Digital Micromirror Device (DMD) as a multiscale measuring tool, and a method of measurement on lateral dimension has been proposed. As an excellent optical modulation device, DMD could modulate incident light to line structure light. Owing to controlling flexibility of DMD, the parameters of the line structure light, include line width, light intensity and scanning frequency, could be modulated by programming. This project has solved the problem of measurement error due to the angle between line structure light and field of view of specimen, and the results of experiment proved that, this method by DMD acquired lateral dimension data conveniently.