Abstract: A microelectrode is combined with micro holes formed by needling through the insulating film of carbon rod. （see Fig.1). The cyclic voltammogram(see Fig.2) of this electrode determined in solution of K3Fe(CN)6/K4Fe(CN)6 are fully identical with the theoretical curves. The limiting diffusion current determined from step scanning volt-ammetry method is in good linear relation with the concentration of K4Fe(CN)6 solution(see Fig.5) and with the square of scanning rate. 　　The cyclic voltammetric curve of Cd2＋ in solution with base electrolyte KCl is an irreversible process(see Fig.3). The current of reduce peak (at －0.98 V vs SCE), determined from step scanning voltammetric method at 800 mV•s－1 scanning rate, is in good linear relation with the concentration of Cd2＋ at 2.55×10－5 mol•dm－3 to 1.28×10－4 mol•dm－3.

Key words: Combinaed micro plate electrode, Cyclic voltamogram, Step scanning voltammetric method, Micro hole, Cadmium