A method for calculating the area of a working region of a self-moving device , wherein the self-moving device is configured to move and work in the working region , and the method comprises: collecting information on the working region by a handheld device in a process of moving the handheld device along the working region , the information at least comprising detected perimeter information of the working region ; generating perimeter data based on the perimeter information collected by the handheld device , the perimeter data comprising data representing the shape and the size of the perimeter; and calculating the area of the working region according to the data representing the shape and the size of the perimeter ; wherein the handheld device comprises a camera and: the collecting comprises capturing a plurality of images of the perimeter in the moving process of the handheld device by the camera of the handheld device ; and characterised in that the generating at least comprises: calculating the perimeter data at least based on related information of the images of the perimeter , and wherein the information of the images comprises a focus length and the generating comprises recording the perimeter by a plurality of mark points set along the perimeter , calculating a distance from the handheld device to the ground by a focus length, and then calculating the length and angle of a line between adjacent two mark points according to the distance from the handheld device to the ground. collecting information on the working region by a handheld device in a process of moving the handheld device along the working region , the information at least comprising detected perimeter information of the working region ; generating perimeter data based on the perimeter information collected by the handheld device , the perimeter data comprising data representing the shape and the size of the perimeter; and calculating the area of the working region according to the data representing the shape and the size of the perimeter ; wherein the handheld device comprises a camera and: the collecting comprises capturing a plurality of images of the perimeter in the moving process of the handheld device by the camera of the handheld device ; and characterised in that the generating at least comprises: calculating the perimeter data at least based on related information of the images of the perimeter , and wherein the information of the images comprises a focus length and the generating comprises recording the perimeter by a plurality of mark points set along the perimeter , calculating a distance from the handheld device to the ground by a focus length, and then calculating the length and angle of a line between adjacent two mark points according to the distance from the handheld device to the ground. the collecting comprises capturing a plurality of images of the perimeter in the moving process of the handheld device by the camera of the handheld device ; and characterised in that the generating at least comprises: calculating the perimeter data at least based on related information of the images of the perimeter , and wherein the information of the images comprises a focus length and the generating comprises recording the perimeter by a plurality of mark points set along the perimeter , calculating a distance from the handheld device to the ground by a focus length, and then calculating the length and angle of a line between adjacent two mark points according to the distance from the handheld device to the ground. <EOS>