In a method and system for detecting a driving state of a driver in a vehicle, a face recognition standard corresponding to an environmental condition within the vehicle is established based on a series of image frames generated by capturing consecutively images of the driver upon movement of the vehicle. Upon detection of a variance in the environmental condition during movement of vehicle, the face recognition standard is updated with a corrected face recognition standard corresponding to the environmental condition with the variance. It is determined based on the corrected face recognition standard and the image frames whether the driving state of the driver is a dangerous state, where the driver's face does not face a front windshield of the vehicle or where the driver's face faces the front windshield of the vehicle but one of the driver's eyes is closed.