The invention discloses a driver fatigue monitoring device based on multivariate information fusion and a monitoring method thereof. The device comprises a digital signal processor, a camera head with a filter, a rectangular ultrared LED light source module mounted on a car windshield, a speaker module and a sensor module comprising an angular sensor and a pressure sensor, wherein the camera head, the rectangular ultrared LED light source module, the speaker module and the sensor module are respectively connected with the digital signal processor. The monitoring method comprises four procedures, namely eye characteristic identification, view line track, driving activity monitoring and fatigue characteristic judgment which merges the fatigue judgment results of the eye characteristic identification, the view line track and the driving activity monitoring to accurately judge the fatigue states of a driver. The invention utilizes an information merging technology to further develop and improve a fatigue driving detection technology, can objectively, rapidly and accurately judge the fatigue state of the driver in real time and avoids traffic accidents caused by fatigue driving.