A three-dimensional displacement measurement method for laser speckle images, comprising the steps of: emitting a first coherent light and a second coherent light; obtaining a first laser speckle image and a second laser speckle image, wherein the first coherent light is incident on a first surface (211, 311, 411, 511, 821, 921, 1021) of a transmission shaft and scatters to generate a first laser speckle and the first laser speckle is recorded to obtain the first laser speckle image, and the second coherent light is incident on a second surface (212, 312, 412, 512, 822, 922, 1022) of the transmission shaft that is perpendicular or adjacent to the first surface (211, 311, 411, 511, 821, 921, 1021) and scatters to generate a second laser speckle and the second laser speckle is recorded to obtain the second laser speckle image; repeating the step when the transmission shaft moves, wherein a third laser speckle image is obtained according to the first laser speckle and a fourth laser speckle image is obtained according to the second laser speckle, and the first laser speckle image is compared with the third laser speckle image to determine a shift direction and a shift distance of the first surface (211, 311, 411, 511, 821, 921, 1021), and the second laser speckle image is compared with the fourth laser speckle image to determine a shift direction and a shift distance of the second surface (212, 312, 412, 512, 822, 922, 1022); and determining a three-dimensional displacement of the transmission shaft by measuring the shift direction and the shift distance of the first surface (211, 311, 411, 511, 821, 921, 1021) of the transmission shaft and the shift direction and the shift distance of the second surface (212, 312, 412, 512, 822, 922, 1022) of the transmission shaft, and utilizing the absolute positioning of actual motion of the laser speckle on the surface of the transmission shaft to correct positioning errors of original rotation angle parameters. emitting a first coherent light and a second coherent light; obtaining a first laser speckle image and a second laser speckle image, wherein the first coherent light is incident on a first surface (211, 311, 411, 511, 821, 921, 1021) of a transmission shaft and scatters to generate a first laser speckle and the first laser speckle is recorded to obtain the first laser speckle image, and the second coherent light is incident on a second surface (212, 312, 412, 512, 822, 922, 1022) of the transmission shaft that is perpendicular or adjacent to the first surface (211, 311, 411, 511, 821, 921, 1021) and scatters to generate a second laser speckle and the second laser speckle is recorded to obtain the second laser speckle image; repeating the step when the transmission shaft moves, wherein a third laser speckle image is obtained according to the first laser speckle and a fourth laser speckle image is obtained according to the second laser speckle, and the first laser speckle image is compared with the third laser speckle image to determine a shift direction and a shift distance of the first surface (211, 311, 411, 511, 821, 921, 1021), and the second laser speckle image is compared with the fourth laser speckle image to determine a shift direction and a shift distance of the second surface (212, 312, 412, 512, 822, 922, 1022); and determining a three-dimensional displacement of the transmission shaft by measuring the shift direction and the shift distance of the first surface (211, 311, 411, 511, 821, 921, 1021) of the transmission shaft and the shift direction and the shift distance of the second surface (212, 312, 412, 512, 822, 922, 1022) of the transmission shaft, and utilizing the absolute positioning of actual motion of the laser speckle on the surface of the transmission shaft to correct positioning errors of original rotation angle parameters.