In order to solve the problem that high power laser far-field measurement can not effectively identify the parameters of each sidelobe peak in any direction of sidelobe beam, a detection method of sidelobe peak parameters of far-field measurement based on sidelobe beam diffraction inversion is proposed in this paper. The main idea is to quantify the sidelobe beam image according to a specific angle sampling interval, and convert the two-dimensional sidelobe beam image into a set of one-dimensional sidelobe beam curves in all directions by angle transformation, then detect the parameters of each sidelobe peak of one-dimensional sidelobe beam curve at each angle, so as to obtain the parameters of each sidelobe peak in any direction of sidelobe beam. The main optimization measures are as follows: (1) Convert the two-dimensional sidelobe beam image into a set of one-dimensional sidelobe beam curves in all directions by angle transformation; (2) Detect the parameters of each sidelobe peak of one-dimensional sidelobe beam curve at each angle, count each sidelobe peak in all directions, and generate the maximum rings of each sidelobe peak; (3) Count the gray mean values of the maximum rings of each sidelobe peak, compare the gray mean values of the maximum rings of each sidelobe peak with the background noise, and select the minimum peak mean value greater than 1.5 times the background noise as the minimum measurable sidelobe peak signal of the whole sidelobe beam. The experimental results show that this method can effectively detect the parameters of each sidelobe peak in any direction of the sidelobe beam. The error between the mean value of gray maximum value and the theoretical value of gray maximum value in any direction is 0.477, and the error between the mean value of the maximum ring radius and the radius of the theoretical value of 5 sidelobe peaks is less than 1 pixel. This method improves the experimental accuracy and reliability of far-field measurement of high power laser based on the diffraction inversion of sidelobe beam, and it will lay a foundation for the accurate measurement of the far field of the high power laser in the large scientific facility in the future.