The invention provides a pedestrian gait detection method based on a terminal device, and the terminal device. The method comprises the following steps: acquiring the attitude angle of the terminal device relative to an earth coordinate system; acquiring the carrying mode of the terminal device; and if the carrying mode of the terminal device is an arm-swinging mode, detecting a pedestrian gait event through the attitude angle. Detection of the pedestrian gait event through the changes of the attitude angle can ensure that a gait detection algorithm has less error in an arm-swinging occasion,normal detection can be realized, operation is simple, and the method can be easily implemented.