Volta was the first to observe the perception of sound on electrical stimulation in 1790. In 1957, Djourno et. al. used the single channel monopolar scala tympani electrode induction coil system as the first attempt for cochlear implant in human. Since then, numerous animal studies and clinical applications have been performed. In this study, author studied brain stem evoked response(BSER) in 5 cats with acoustic stimulation, conventional electrical stimulation and 50 KHz amplitude modulated electrical stimulation. The purpose of the study was to find out the type of ideal electrical stimulation for generating BSER. Results were as follows : 1) Bipolar method showed more clearly both the wave form and the frequency specificity of BSER than monopolar method. 2) Amplitude modulated electrical stimulation showed more clearly both the wave form and the frequency specificity of BSER than conventional electrical stimulation. 3) Amplitude modulated electrical stimulation showed similar results with those of acoustic stimulation with regard to the wave form and the frequency specificity of BSER. Based on the above results obtained, it was concluded as follows ; Amplitude modulated electrical stimulation using bipolar method seems to be a better way of electrical stimulation on cochlear implant.