An image denoising method, comprising: performing preliminary denoising processing to an acquired image to be processed, so as to obtain a preliminarily denoised image; calculating a residual quantity corresponding to a central pixel of each unit area in the image to be processed according to numerical values of specific energy parameters to which the image to be processed and the preliminarily denoised image correspond, respectively, wherein the residual quantity is an absolute value of a difference between a gray scale value of the acquired image to be processed and a gray scale value of the preliminarily denoised image; and using the residual quantity to calculate a weight matrix corresponding to each unit area, and performing non-local mean value calculation to the image to be processed according to the weight matrix, so as to realize the denoising processing of the image to be processed, wherein a process of calculating the weight matrix comprises: selecting an arbitrary unit area in the image to be processed, and determining an associated area of the arbitrary unit area in the image to be processed; and calculating a weight value corresponding to each associated unit area according to a value of a distance between each associated unit area in the associated area and the arbitrary unit area and the residual quantity, so as to obtain the weight matrix, wherein the weight value corresponding to an arbitrary associated unit area in the associated area is calculated by using the formula below: w n m = e − d n m + residuals n m / h where, w(n, m) is the weight value to which an arbitrary associated unit area (n, m) corresponds, d(n, m) is the value of the distance between the arbitrary associated unit area and the arbitrary unit area, residuals(n, m) is the residual quantity corresponding to the central pixel of the arbitrary unit area, h is a predefined control coefficient. performing preliminary denoising processing to an acquired image to be processed, so as to obtain a preliminarily denoised image; calculating a residual quantity corresponding to a central pixel of each unit area in the image to be processed according to numerical values of specific energy parameters to which the image to be processed and the preliminarily denoised image correspond, respectively, wherein the residual quantity is an absolute value of a difference between a gray scale value of the acquired image to be processed and a gray scale value of the preliminarily denoised image; and using the residual quantity to calculate a weight matrix corresponding to each unit area, and performing non-local mean value calculation to the image to be processed according to the weight matrix, so as to realize the denoising processing of the image to be processed, selecting an arbitrary unit area in the image to be processed, and determining an associated area of the arbitrary unit area in the image to be processed; and calculating a weight value corresponding to each associated unit area according to a value of a distance between each associated unit area in the associated area and the arbitrary unit area and the residual quantity, so as to obtain the weight matrix, wherein the weight value corresponding to an arbitrary associated unit area in the associated area is calculated by using the formula below: w n m = e − d n m + residuals n m / h where, w(n, m) is the weight value to which an arbitrary associated unit area (n, m) corresponds, d(n, m) is the value of the distance between the arbitrary associated unit area and the arbitrary unit area, residuals(n, m) is the residual quantity corresponding to the central pixel of the arbitrary unit area, h is a predefined control coefficient.