A method for estimating a distance to a target, applicable to an unmanned aerial vehicle comprising a photographing device, characterized by comprising: acquiring a current frame of image of the target captured by the photographing device; acquiring location information of the target according to the current frame of image, wherein the location information comprises a height of the target and two-dimensional pixel coordinates of the target in the image; acquiring attitude information of the photographing device, wherein the attitude information comprises a pitch angle of the photographing device; acquiring a smallest circumscribed rectangle of the target, where the two-dimensional pixel coordinates of the target in the image are two-dimensional pixel coordinates of the smallest circumscribed rectangle in the image, and the two-dimensional pixel coordinates of the smallest circumscribed rectangle in the image comprise an ordinate v min of a highest point of the smallest circumscribed rectangle and an ordinate v max of a lowest point of the smallest circumscribed rectangle; acquiring an angle φ formed by a line connecting the highest point of the smallest circumscribed rectangle and the photographing device and a line connecting the lowest point of the smallest circumscribed rectangle and the photographing device; acquiring an angle δ formed by the line connecting the lowest point of the smallest circumscribed rectangle and the photographing device and a vertical direction according to the pitch angle θ of the photographing device; and acquiring the distance d between the target and the unmanned aerial vehicle according to the angle φ and the angle δ. acquiring a current frame of image of the target captured by the photographing device; acquiring location information of the target according to the current frame of image, wherein the location information comprises a height of the target and two-dimensional pixel coordinates of the target in the image; acquiring attitude information of the photographing device, wherein the attitude information comprises a pitch angle of the photographing device; acquiring a smallest circumscribed rectangle of the target, where the two-dimensional pixel coordinates of the target in the image are two-dimensional pixel coordinates of the smallest circumscribed rectangle in the image, and the two-dimensional pixel coordinates of the smallest circumscribed rectangle in the image comprise an ordinate v min of a highest point of the smallest circumscribed rectangle and an ordinate v max of a lowest point of the smallest circumscribed rectangle; acquiring an angle φ formed by a line connecting the highest point of the smallest circumscribed rectangle and the photographing device and a line connecting the lowest point of the smallest circumscribed rectangle and the photographing device; acquiring an angle δ formed by the line connecting the lowest point of the smallest circumscribed rectangle and the photographing device and a vertical direction according to the pitch angle θ of the photographing device; and acquiring the distance d between the target and the unmanned aerial vehicle according to the angle φ and the angle δ.