The invention relates to the field of information processing technology and sensor signal processing, and particularly relates to a time-domain self-adaptive automatic speech detection method based on dynamic noise estimation. According to the invention, based on time-domain short time energy of sound and frequency-domain short time energy variation in a certain range, speech detection is carried out; and finally, the optimal result is selected according to dynamically estimated magnitude of background noise energy. The accuracy of speech recognition is greatly improved. The adaptability of speech recognition to environmental change is improved.