The accuracy of second side impulse measurement system is of great importance to the impulse voltage measurement. For the judgments to measurement accuracy of impulse voltage measuring software，test data generator of IEC61083-2010 was used to test the software. When the test data corresponds to low-sample rate acquisition card or oscilloscope ，some calculation result of the software will be out of limited error. To improve the calculation resulsts of soft，interpolation was used in the software to simulation the waveform data acquaint from the oscilloscope. After interpolation process to the software，test results are on under the limited error，now the impulse measurement software can be well used in lighting impulse waveform measurement.