Abstract: With the help of numerical method and the Hodgkin-Huxley equation of neural cell membrane potential‚the effect of external stimulus such as direct current‚alternating current and noise on the potential spike of neural cell membrane was investigated．By analyzing the amplitude‚frequency and twonear -spike distance of potential spike after the stimulus‚a decreasing relation between the intensity of external direct -current stimulus and the amplitude of stimulated potential spike was found．Complicated
amplitude windows and frequency windows were observed corresponding to the intensity and amplitude of alternating current stimulus．With the increase of stimulus intensity‚the Gauss white noise can destroy the rhythm of potential spike．

Key words: neural cell, action potential, spike．