A method to acquire the coordinates of camera and measured surfaces in the deflectometry is proposed. A circular window glass is tested by the slope calculation and the shape reconstruction. The final test results by the proposed method are close to those by the interferometer and the Zhang's calibration method, and the feasibility and correctness of the proposed method are proved. The research results show that the calibration by the proposed method is simple and flexible. This method can be used to achieve the global calibration of cameras and the measured surfaces, and is suitable for the calibration of online measurements.