Abstract: The equipment of Micro Unmanned Aerial Vehicle (MUAV) was limited by weight. In this paper, the coordinate solver model based on machine vision was introduced, and on this basis, the iterative approximation algorithm which was based on Digital Elevation Model (DEM) was considered to get the altitude difference between the Unmanned Aerial Vehicle (UAV) and the target in order to locating the ground target caught by the optronics pod with the airborne equipment of an MUAV autonomously. The computer simulations and the flight experimental results from program which was transplanted to the airborne devices showed that the coordinate solver model combined with the iterative approximation algorithm could calculate the position of ground target in the video stream (25fps) timely and accurate.