The change of the outgoing laser pulse power has a great influence on the accuracy of atmospheric lidar data collection， so it is necessary to detect the power of pulsed laser accurately. Based on the characteristics of the narrow pulse width and high repetition frequency of the outgoing laser pulse， we proposes a power detection system for narrow pulsed laser. First， the photoelectric conversion circuit composed of photodiodes is used to realize the photoelectric conversion of the laser signal. Second， the transconductance type peak hold circuit is used to hold the peak value of the laser single pulse. Finally， the synchronous trigger signal is used to collect the peak value of the single chip and measure the outgoing pulse power of the pulsed laser. After experimental testing， the system is suitable for power detection of laser pulses with a pulse width of 10 ns， a repetition frequency of 10 kHz， and a wavelength of 532 nm used by atmospheric lidar. The test results have good linear relationship and accuracy compared with standard laser power meters， which can meet application requirements.