The invention relates to a fatigued drive detection method based on mouth features. The fatigued drive detection method comprises the following steps that a face detection classifier is established; drive state images of a driver are collected in real time; the mouth of the driver is accurately positioned in the drive state images; in continuous video images, according to the position of the mouth in the image of the last frame, the position of the mouth in the image of the current frame is accurately predicted; according to the predicated position of the mouth, the position of the mouth is accurately positioned, the opening degree of the mouth of the driver is judged, and according to the ratio of the number of frames with large mouth opening degrees within unit time, whether the driver is in the fatigue drive state or not is judged; if the driver is in the fatigue drive state, an alarming reminding is conducted or a real-time video of the driver in the fatigue drive state is sent to a remote server, and a remote order is received. The fatigued drive detection method has the advantages that the monitoring accuracy is high, the leak detection and false detection rate is low, the environmental influence is small, the speed is high, and the cost is low.