A new method is proposed to solve problem of extrinsic parameters calibration of pinhole camera and 3D LiDAR.The problem is converted into solving the rotation and scaling matrix in the three-dimensional space according to the correspondence of chessboard in camera coordinate and 3D LiDAR coordinate systems.Each frame data can provide 4 constraints and at least 3 frames data can solve extrinsic matrix. The calibration approach is clear and easy to understand and it can be used to explain the degenerate configuration reason.Simulation and real experimental data show that the method can get high precision extrinsic matrix and can obtain better calibration results with limited sampling frames.