The present invention relates to the augmented reality field, in particular relates to a geographic grid and image identification combined outdoor mobile augmented reality method. The outdoor mobile augmented reality method comprises the following steps of the outdoor scene area acquisition, the spatial data processing, the geographic grid unit division, the target data acquisition, the image feature point detection and extraction, the spatial quadtree index, the sample database generation, the terminal data acquisition, the image feature generation, the data analysis and matching, the scene information 3D registration and the scene augmented reality display. The outdoor mobile augmented reality method of the present invention can better overcome the influence of the factors during an image identification process, such as the translation, the rotation, the scale zooming, the brightness change, etc., at the same time, by adding the color information in a descriptor, the problem that thegray change similar areas generate the mismatching problem easily is solved, by combining a geographic information technology, the image features having the similar textures can be distinguished according to the positions, by utilizing the division of the geographic grids, the sample point information quadtree indexes are established, and the rapid and accurate matching can be carried out in a mass feature database.