An excimer laser pulse energy detection system was introduced, which is able to pick out either a single pulse energy or the individual energy of a desired series of pulses during the laser runs in a pulse repetition mode up to 200 Hz. By use of a pyroelectric detector as energy sensor the system consists of amplifiers, peak-holding circuits, MCU, display and communication interface. Owing to an excellent interference suppressor circuit design the system runs well even if the thyratron discharging EMI is very strong. Testing on the 193 nm ArF and 248 nm KrF excimer laser, response time of 4 ms, power resolution of 10 μJ, sensitivity of 0.5 V/mJ and power accuracy of ±3% are achieved. This system can be used as an energy-meter alone or as a real time detector in a closed feedback loop for laser pulse energy stabilization. After substituting the pyroelectric detector with a photomultiplier tube, it is expected that the system can be suitable for repetition rate higher than 1 kHz.