Abstract: The micro plane explosion switch applied in the exploding foil initiator system consists of two main electrodes and one trigger electrode. An investigation on the influence of Al/CuO reactive multilayer films (RMFs) additives on the trigger electrode was performed. The trigger electrode has been characterized with scanning electron microscopy, differential scanning calorimetry and the atomic emission spectroscopy double line technique. The heat released in the thermite reaction between Al film and CuO film was found to be 1537 J/g. The reaction temperature curves reached to the peak in about 0.5 s, and then dropped to a relatively stable temperature. Firing characteristics of the switch were accomplished using the designed experiment set up. The result shows that the peak and rise time of the discharge current were 1938 A and 390 ns for Cu/Al/CuO RMFs when main voltage was 2000 V, which was better than the trigger electrode only consisted of Cu film.