In this paper we advanced a design idea about a real time measuring system which composed of an oscillograph and PIN photoelectric cell detector,using this system pulse width and energy of high repetition rate pulsed laser can be measured simultaneously.Also this system solves some technical problems effectively,such as transform of photoelectric signal,data processing and transmission.Thus,we can obtain pulse width and energy of every laser pulse in the sequenced laser pulses of 20 Hz repetition rate pulsed laser.