Optimization methods of camera's exposure time based on line structured light stripe reliability evaluation are studied, and the reliability evaluation results are used as reference indexes for optimization of exposure time. Firstly, existing light stripe reliability evaluation model is improved by combination with the characteristics that light stripe cross section obey Gaussian distribution, and then Gaussian reliability evaluation model is constructed. With the extraction method of sub-pixel light stripe center, light stripe centers are extracted from stripe images acquired with different exposure times. Extraction results are evaluated by Gaussian reliability evaluation model to obtain the values of evaluation reliability C and gray level R. Then, the influence mechanism of exposure time t on the evaluation results are analyzed respectively. Variation models of t-C and t-R are built, and the camera's optimal exposure time is finally obtained through analysis of variation models. Experiments take the high-precision spline and cement pavement model under light intensity of 230 lux as an experimental measurement object. Results show that measurement with the optimized exposure time is more reliable and more efficient. Mean residual sum of squares of the single light strip measurement is about 0.03 mm 2. The average texture depth of reconstructed model is only 9.8% away from actual model.