With the development of full-screen mobile phones, the need for under-screen imaging of mobile phones has emerged. However, the diffraction caused by the wiring and other opaque parts will affect the image quality of the under-screen image. In this article, under-screen image is restored from the perspective of image restoration. The point spread function (PSF) of the mobile phone imaging system is obtained through actual measurement, and the image is deconvolved using the measured PSF. In this article, traditional deconvolution method has been improved, in which the color space of the image is converted and different channels are processed separately. Compared with the traditional deconvolution method, the results of the sub-channel deconvolution method have improved structural similarity (SSIM), peak signal-to-noise ratio (PSNR) and other indicators, and the required running time is shorter. After sub-channel deconvolution, the non-local averaging algorithm is used for denoising, which further improves the quality of the under-screen image.