A method for high-precision true color three dimensional reconstruction of mechanical component. Firstly performs image acquisition: the left and right high-resolution grayscale cameras are fixed at same height and spaced at certain distance, an optical transmitter fixed between the two grayscale cameras, and low-resolution color camera fixed above optical transmitter, thus images of measured high-precision mechanical component are shot. Then performs image processing: all images are transmitted to a computer, which uses image processing to record surface information of measured high-precision mechanical component in the point cloud by high-precision true color three-dimensional reconstruction, which reflects color texture information of the surface, so as to realize the non-contact high-precision true color three dimensional reconstruction of high-precision mechanical component. The method uses binocular high-precision grayscale cameras instead of binocular color cameras, which broadens the range of capture wavelengths, retains richer texture details of high-precision mechanical component and improves accuracy of measurement.