A method for determining a spatial parameter based on an image displayed by a display device, comprising: determining (S101, S201, S301) a first pixel coordinate corresponding to a first position on an image displayed on the display device, and a second pixel coordinate corresponding to a second position on the image; determining (S102) an image distance between the first pixel coordinate and the second pixel coordinate; and determining (S103, S206, S304) a spatial parameter between the first pixel coordinate and the second pixel coordinate according to the image distance, an object distance, and the focal length of the lens in a camera apparatus used to photograph the image, characterized in that determining (S101, S201, S203) the first pixel coordinate corresponding to a first position on an image displayed on the display device, and a second pixel coordinate corresponding to a second position on the image comprises: performing edge detection on the image; and determining whether the first pixel coordinate is located in the center of a first photographed object in the image and whether the second pixel coordinate is located in the center of a second photographed object in the image, and when it is determined that the first pixel coordinate or the second pixel coordinate is not located in the center of the respective photographed object, prompting the user to adjust the first pixel coordinate or the second pixel coordinate; or, determining whether the first pixel coordinate and the second pixel coordinated are respectively located at two ends of a photographed object in the image and when it is determined that the first pixel coordinate or the second pixel coordinate is not located at a corresponding end of the photographed object, prompting the user to adjust the first pixel coordinate or the second pixel coordinate. determining (S101, S201, S301) a first pixel coordinate corresponding to a first position on an image displayed on the display device, and a second pixel coordinate corresponding to a second position on the image; determining (S102) an image distance between the first pixel coordinate and the second pixel coordinate; and determining (S103, S206, S304) a spatial parameter between the first pixel coordinate and the second pixel coordinate according to the image distance, an object distance, and the focal length of the lens in a camera apparatus used to photograph the image, determining (S101, S201, S203) the first pixel coordinate corresponding to a first position on an image displayed on the display device, and a second pixel coordinate corresponding to a second position on the image comprises: performing edge detection on the image; and determining whether the first pixel coordinate is located in the center of a first photographed object in the image and whether the second pixel coordinate is located in the center of a second photographed object in the image, and when it is determined that the first pixel coordinate or the second pixel coordinate is not located in the center of the respective photographed object, prompting the user to adjust the first pixel coordinate or the second pixel coordinate; or, determining whether the first pixel coordinate and the second pixel coordinated are respectively located at two ends of a photographed object in the image and when it is determined that the first pixel coordinate or the second pixel coordinate is not located at a corresponding end of the photographed object, prompting the user to adjust the first pixel coordinate or the second pixel coordinate. <EOS>