A germanium wedge needs a special mechanism for the measurement of its angle.This paper presents improved mechanism for a precision test of the angle.Compared with the old mechanism,it uses 720 multiteeth graduation device as its base and screw lever mechanism instead of previous waving rob structure to perform its rotation around the optical axis.All these,together with divided driving skill under the control of a computer,make good use of advantages of auto search method and make the measurement more efficient and more accurate.The device can also be used for other purposes,such as optical components and graduation of angle.