The reactive pulse generator could generate high-power electromagnetic pulse by the rapid chemical reaction. The principle of the generator is to produce the required environment for chemical reaction by explosion. In order to study the impact of the explosion mode on the pulse，the typical Φ26 mm pulse generator is studied by the test. Three experiments are designed and carried out, including end surface point detonation test，both ends detonation test and centrality detonation test. According to the test results，when the charging voltage is 5 kV，the centrality detonation test could produce the maximum pulse voltage, and the end surface point detonation test could produce the minimum pulse voltage; the pulse voltage changes with time of impact wave according to a quadratic curve.