An image based adaptive finite element mesh division method belongs to a mesh division method for finite element analysis of a material structure. The method comprises: 1, distinguishing different phases or components in an image with an image analysis method; 2, reading position information of all pixels into a computer memory by utilizing a computer language program; 3, according to the fineness of a spatial structure, reducing an image resolution of a region thick and big in structure and single in component; 4, directly constructing a finite element unit by the pixels, wherein different resolutions cause different mesh densities; and 5, transiting meshes different in density by mesh mapping. According to the method, nodes and units are directly constructed by utilizing images, and solid modeling is skipped, so that system resources can be saved; moreover, a mesh structure can be optimized on the premise of ensuring calculation precision, so that the number of nodes is remarkably reduced, the calculation time is shortened, and the memory consumption is reduced; and the whole process is automatically completed, so that the method is very practical for a model with a huge amount of nodes.