Abstract: Precision measurement of mini-rotating-angle is of significance in practice engineering applications.In order to measure mini-rotating-angles with much higher precision,a new method was presented combining the digital holographic,double-exposure of interferometry with image processing.Through detailed theoretical analysis and experimental verification,the Young's modulus of steel wires was measured with this method,and its error was only 1.1%.Results indicate that the method can be widely used in practical application because of its high accuracy,strong feasibility.The results are helpful for the future design of more perfect goniometers.