Lightning protection system is a system that is very necessary at this time, given the growing electrical appliances rapidly. This system protects us and our electrical appliances from direct strikes. In Indonesia itself as a region with high lightning intensity. In general, external lightning protection system consists of two namely Active protection system and Passive protection system. In this research will discuss about simulation of lightning protection system with reversing method by applying the working principle of Op-Amp in MATLAB where in the test will compare two finials by measuring the electric field strength between the two, where one of the finials will be installed the reversing device, and he gave a spark gap for the protection of the equipment. Large testing of this protection tool using impulse voltage up to 150 KV. In the test just use the voltage parameters. Once tested there will be a comparison with the results of calculations and previous models.