In order to measure initiation pulse current more accurately, put forward a method of sampling and curve-fitting project to measure the signal. Upper computer software read the sample data stored in the FIFO via the ISA bus, the data acquisition module was devised based on high-speed ADC and FIFO, which was used to sample and storage the single damped sine wave, to do the curve fitting according to the sampling results. The fitting results show that the method can accurately measure the magnitude and the cycle of the signal, and also can draw out the waveform.