The invention discloses a phase amplification calculation method based on black component structured light scanning. The method comprises the following steps of: pre-processing the structural light; generating a projection grating; capturing an image of the surface of the black piece; magnifying the gray value of each pixel of the surface image of the black piece; calculating the phase of each pixel based on the gray value of the pixel after the amplification process. The phase amplification calculation method based on black component structured light scanning captures an image by projecting aprojection grating onto the surface of the black piece, and enlarges the gray value of each pixel in the image, and calculates the phase of each pixel point using the gray value of the enlarged pixelpoint, which can reduce noise interference and effectively improve the phase calculation accuracy.