Abstract: A calibration method of camera parameters based on planar grid was proposed to deal with the problem of intrinsic and extrinsic parameters calibration for photoelectric measuring device in coal bin. Two values of black and white are used to divide pattern on the calibration plate, and the intersection points of black and white values are taken as calibration points. Imaging postures with different perspectives are considered to obtain position information as many as possible. According to rotation invariance of angle feature, Harris algorithm is used to extract angular points, and nonlinear optimization method is adopted to calibrate parameters. The industrial tests are taken in coal bin of Daliuta coal mine of Shendong Coal Group. The test results show that the method can achieve better calibration results of coal level, and error is accepted, which meets needs of depth estimation of coal level in coal bin.