Abstract: How to determine the projection position of mining right boundary on the vertical projection chart has important practical significance for accurately delineating the scope of resource reserves estimation. Based on adequate study of the resource reserves estimation process, the author combined the current common geological mapping softwares, such as MapGIS and AutoCAD, constructed the three-dimensional mathematical model of the ore body, and deduced the trigonometric function to obtain the formula for determining the projection position of the mining right boundary on the vertical and horizontal projection map of the resource reserve. The projected position of the mining right boundary can be determined quickly and accurately on the vertical projection map of resource reserves. This method can provide data support for reasonable exploitation and utilization of resource reserves within the scope of mining right, and also provide technical support for the mining administrative department to approve and supervise resource reserves within the scope of mining right.