An SPE composite microdisk electrode is made by pressing a microdisk electrode on a piece of SPE membrane. It has a small ohmic drop and shows good reproducibility and some well-developed cyclic voltammograms and steady-state polarization curves are obtained. The electrochemical behavior of nitrobenzene and ferrocene at different microelectrode/SPE membrane interfaces is investigated. It is found that electroactive compounds in the vicinity of the interface diffuse from the bulk solution to the electrode surface through the SPE membrane. This technique is suitable for investigating the electrochemical behavior of gases at the metal/SPE interface or organic electroactive compounds poorly soluble in aqueous solution without addition of supporting electrolyte.