Abstract: Electromagnetic emission technology typically requires a pulsed power supply to have a pulse current with an amplitude of tens of kiloamperes and a pulse width of several milliseconds, and to be capable of continuous emission at a repetition rate. Metallized film capacitors are widely used in pulse power supplies due to their high energy storage density and long life. According to the structure of the pulse capacitor and the working mode of the pulse power supply, this paper first establishes the heat generation and heat dissipation model of the pulse capacitor, then establishes the transient temperature field model in the multiphysics simulation software COMSOL Multiphysics 5.6, and combines with the existing experimental results to verify the validity of the model. The accumulation phenomenon of the internal temperature rise of the metallized film pulse capacitor in the repetitive frequency pulse discharge application is discussed. The calculation results show that under the conditions of pulse discharge peak value of 1kA, ambient temperature of 15℃, and metal film thickness of 4nm, the maximum temperature rise of the pulse capacitor core is 22.9℃ after continuous operation for 10 times at a repetition rate of 12 times/min and a time interval of 30s. On this basis, the influence of four factors including ambient temperature, repetition frequency, pulse current peak value and electrode thickness on the temperature rise of the pulse capacitor is analyzed by simulation. The model gives the internal transient heating law of the pulse capacitor under high frequency and high current, which can provide a reference for the reasonable operation and optimal design of the pulse capacitor.