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With the improvement of machining automation, more and more requirements are proposed in surface roughness measurement, which mainly includes measurement methods improving, improvement of measurement accuracy and assessment of roughness parameters. Around these requirements, this paper study measurement method in comparison, the measuring principle of laser triangulation is analyzed and the theory of trigonometric functions is used to derive measuring principle; Principle of the measuring instrument overall structure is studied, the types and parameters of component is selected, then measuring instrument test bench is established, Three-dimensional roughness assessment parameters theory is analyzed, On the basis of theory, experimental measurements of surface roughness is conducted, and verify the theoretical analysis with experimental data.By the depth analysis and research of laser triangulation measuring principle, and though the analysis of direct laser triangulation and symmetric oblique optical laser triangulation, CCD pixel displacement is changed by the trigonometric relationship, which reach the height information formula of the measured micro-surface; Comparison between direct laser triangulation and symmetric oblique-type triangulation, direct-style triangulation obtain that simple structure, larger measuring range, but lower resolution. The analysis of triangulation measurement on surface roughness measurements, obtain the direct-type triangulation as surface roughness measurement method.Though the study of measurement methods and component structure principle, it is established that a new type of surface roughness measuring instrument, CCD laser probe uses the combination both Ernostar optical system and Li-CCD, which have good linearity, XY work platform is combined with static flotation rail and linear motors, which achieve high-precision positioning and smooth movement, Column is matched by the stepper motor and ball screw, which meet the exact lift mobile in height.Study of the three-dimensional roughness evaluation parameters, reaches least squares base level established method and the eight of basic roughness evaluation parameters. The processed plane is studied, then the parameters of both two-dimensional and three-dimensional are assessed on experimental data, then the assessment results are compared, which obtain that evaluation of two-dimensional parameters with the limitations and evaluation of three-dimensional parameters with integrated features.
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