The invention provides an in-place precision measurement method for a three-dimensional shape error of an aspheric grinding circular arc diamond grinding wheel. The in-place precision measurement method comprises the steps that (1) height data of all points on the surface of the grinding wheel are spirally and continuously scanned and measured; (2) the data are subjected to interpolation fitting treatment according to a spiral trajectory model, a three-dimensional geometrical morphology matrix on the surface of the grinding wheel is obtained, and least square circular arc fitting is conducted, so that the circular arc radius, the circular arc center coordinate and the circular arc center deviation of the grinding wheel are obtained; (3) an average three-dimensional geometrical morphology matrix on the surface of the grinding wheel is established and subtracted from the morphology matrix, and a three-dimensional error distribution matrix, a circular arc degree error and a radial run-out error are obtained; and (4) outer circumference height data of the grinding wheel are measured, and the basic part radius of the grinding wheel is obtained through least square circular arc fitting. According to the in-place precision measurement method for the three-dimensional shape error of the aspheric grinding circular arc diamond grinding wheel, efficient precision non-contact measurement of all the important geometrical parameters of the circular arc diamond grinding wheel is achieved, and the measurement results can be directly used for precise interpolation calculation of aspheric optical element ultra-precision grinding machining grinding wheel movement control point coordinates.