The invention discloses a method for measuring a real photon number of a discharge fault using ultraviolet power equipment. The method comprises the following steps: S1, imaging a corona discharge fault point via an ultraviolet imager to obtain an original photon number N; S2, recognizing a pixel number P corresponding to the diameter direction of target electrical equipment of the discharge fault point; and S3, calculating a real discharge photon number N0 of the discharge fault point. The invention further discloses a device for measuring a real photon number of a discharge fault using ultraviolet power equipment. The device comprises the ultraviolet image, an input module and a calculation module. The method is simple, and can timely and passively acquire the distance between the fault point to be measured and the observation point without using ranging equipment and calculate the real discharge photon number of the discharge fault point.