A monocular vision based real-time location system for products on a conveying belt comprises a camera. The camera is arranged above the head end of the conveying belt and is connected with a computer. A calibration plate is arranged in a location region of a static conveying belt. A monocular vision based real-time location method for products on the conveying belt comprises the steps of building a world coordinate system; measuring world coordinates of a projection point of the camera in the conveying belt plane; producing a viewing frame picture; detecting the edges of the picture to obtain the picture only with the product edges; separating the products in a line scanning mode; performing column scanning on the single product in the picture to obtain the product lower boundary; calculating world coordinates of points of the lower boundary in the picture, and calculating the distance between the points of the world coordinate system along the conveying belt and the projection point to fine the closest point and the shortest distance, wherein the closest point is the location point, and the shortest distance is the location distance. By means of the steps, the monocular vision based product real-time location is achieved.