For solving the problems of calibration of the turntable position accuracy and measurement of its pitch angle at the same time

a new method for measuring two dimensions tiny angular displacement is proposed.In optical path of the laser autocollimation

DSP and self scanned photodiode array（SSPA）are used to capture the moved displacement of the image of V shape graduation which fixed in the focal plane.Based on the principle of optical imaging and the form of image

the incidence relation between the displacement and a angle is established.A measurement accuracy of 0.9″can be achieved

and the requirements for calibrating turntable can be met.