The wavelength of the terahertz is between the infrared and the microwave, and the photon energy is low, so it has great application prospects in security inspection. In order to further improve the target resolution of terahertz passive imaging system, A terahertz image enhancement method based on a block matching and three-dimensional and weighted Schatten-p norm minimization is proposed to improve the image resolution of terahertz passive imaging system. It uses three-dimensional matched filtering to remove image noise on the basis of mean filtering, and then adopts Lucy Richardson algorithm and weighted Schatten-p norm minimization for image restoration. Finally, the convolution filter is used to enhance image details and the background of the image is subtracted by the edge detection. The method of paper significantly enhances the image contrast and increases system resolution from 2cm to 1.5cm, effectively improving system performance.