The present disclosure provides a method and device for counting pedestrians. The method comprises: reading a pedestrian depth image, and comparing the pedestrian depth image and a pre-acquired environmental mean image to acquire a foreground image; dividing the foreground image into a plurality of regions, detecting whether or not there is a step in an edge pixel point of each region, and detecting whether or not the region surface formed in each region coincides with the curved surface of the head top; determining that the currently detected region is the region of the head top when there is a step in the point and when the region surface coincides with the curved surface; and counting and outputting the number of pedestrians according to the region of the head top determined from the pedestrian depth image and the region of the head top determined from an adjacent pedestrian depth image.