Abstract: When the electron multiplier (EM) works in a pulse condition, the discrete signals are output on its anode. Since the electron multiplication process has a certain statistical law, to study the performance parameters of the EM in a pulse condition, the substantive tests and analyses of the pulsed signal output from the anode were required. The photomultiplier tube (PMT) based on a dynode EM was taken as an example, by changing the incident light intensity to make it work in a pulse condition, a high-bandwidth and high-sampling-rate oscilloscope was used to collect its anode output signal. A graphical data analysis software was developed based on Python to perform the offline analysis on a large number of pulse signal data collected by an oscilloscope, and performance parameters such as charge integral spectrum, gain, resolution, post-pulse rate, and leading-edge time of PMT could be obtained. The software adopted a modular structure, and each module could work independently according to the different test requirements. The proposed software can quickly analyze the performance parameters of the EM in a pulse condition, and provides a convenient analysis method for the optimization of the EM fabrication process and its application in the field of weak signal detection.