A kind of ultraviolet pulse laser energy detection system based on PIN photodiode was introduced. Firstly, the light outside main optical path was used to realize nondestructive and real-time pulse energy detecting. Secondly, high-speed and high-precision integral circuit was designed to process photocurrent signal for voltage peak. Finally, the synchronous trigger signal of laser system was used for timing sequence design. Thus, the accurate voltage difference was obtained and the exact laser pulse energy can be calculated. Tested on 248 nmKrF and 308 nmXeCl excimer laser, the real-time nondestructive measuring was realized while the laser ran in a pulse repetition mode up to 200 Hz. The relevance and repeatability of the measuring data were in accordance with the results of the external energy meter of output end and the system meets the application requirements.