A simple and effective test method is designed based on the principle that self-healing could cause the voltage falling between the under test capacitor’s electrode and makes the parallel capatior charge up for its charge loss. This method utilizes oscilloscope to monitor the pulse voltage signal produced by the pulse current signal from the charge up operation on the sampling resistance，taking this signal as a symbol of self-healing occurrence and calculating self-healing energy loss according to this signal’s character. Simulation result and real test show this method could detect self-healing’s occurrence and calculate self-healing energy loss precisely. Data from 30 test samples revals that, comparing the energy loss given by this method with the real self-healing energy loss, the error is about -3.83%-5.71%，and the precision is comparatively good.