In order to detect the uniformity of the optical output light spot, a method based on imaging method for detecting the uniformity of the optical fiber spot using the regional averaging method was proposed. Firstly, the digital camera was used to acquire the light spot from the experimental device. Then, the regional averaging method was used to detect the uniformity of the image, and the uniformities of the whole area and each small area were calculated to get the area with the best image uniformity. At the same time, the concept of uniform depth was introduced as a basis for judging the uniformity of the light source. The results show that the uniformity of the spot after adjustment reaches more than 99.7%. Through the comparison of the light spot obtained by the experimental apparatus before and after adjustment, and the comparing with the theoretical calculation of the optical fiber output spot distribution, the validity of the method can be verified.