In 1987, Kemp originally recorded stimulated otoacoustic emission in external auditory canal using miniature microphone set. It was minute acoustic component reflected from threshold sensation stimulation. Since then this phenomenon called 'Kemp echo' has been studied in various animals and men with both normal and impaired hearing by several investigators. In this study the change of otoacoustic emissions in various conditions of stimulation and acquisition was investigated and the results were compared with the reported data to explain the characteristics of stimulated otoacoustic emissions. The results were as follows ; 1) Simulated otoacoustic emission was identified in all normal hearing examinees (20 persons). In response to 100μsec click, emission threshold was 9.5dB SL on average. In case of tone bursts, 10, 7, 7.5 and 11 dB SL on average in response to 0.5, 1.0, 1.5 and 2.0 kHz stimulation, respectively. 2) The wave patterns of emission showed some individual variations in response to click, but major emission frequency was around 1.0kHz. In case of tone bursts, emissions were almost equal in frequency, especially in response to 1.0 and 1.5 kHz. 3) The stimulated otoacoustic emission showed absolute phase dependence. In response to alternating simuli, there were no emissions as compared to typica emissions of one phase stimuli. 4) No change of emissions was detected in response to the change of stimulation rates from 5.7/sec to 34.2/sec. 5) The emission was prolonged according to the duration of stimulation. 6) The amplitude of emission was saturated at about 40~50 dB SL and its duration was prolonged as intensity of stimulation increased. 7) The frequency of emission reflected that of stimulation sound. The above results suggested that stimulated otoacoustic emission might be a simple projection of microvibration mechanics of hydraulic cochlear environment in contrary to the active process of impedance change which was proposed by Kemp originally.