A measurement method of two-dimensional small-angle is proposed in this paper. This method is based on laser diodes, dual-axis charge coupled devices (CCD) camera, and a series of reflections between two first-surface mirrors. Measurement accuracy is improved as the laser beam is reflected back and forth several times between the mirrors. Analytic ray tracing is used to model the reflected light ray so as to determine the system equations implicitly in terms of the measured angles. A 2-dimensional high-precision tunable plane mirror is used to simulate the deflection angle. The real-time position changes of the laser spot on the tunable plane mirror are recorded by means of CCD camera; and the position coordinates of all laser spots in pictures are obtained by digital image processing methods and sub-pixel weighted centroid algorithm. According to the centroid coordinate changes of laser spot, the deflection angle of the measured object is obtained. To validate the system, a prototype is built. Calibration and stability experiments are performed. Experimental results show that the resolution, accuracy, and measurement range are, respectively, 0.02, 0.1, and 720 arc sec.