Abstract: The focused ion beam-scanning electron microscopy (FIB-SEM) combining powerful imaging and analysis performance of electronic optical tube with excellent processing capability of focused ion beam tube has become one of the important methods for preparing transmission electron microscopy (TEM) samples. With the continuous expansion of the application fields of FIB-SEM dual beam system, the types of materials applied to FIB-SEM are becoming increasingly diverse, and the preparation samples are also no longer limited to homogeneous materials, for example, heterogeneous materials with uneven organizational structure and composition. Due to the high difficulty and low success rate in preparing TEM samples of heterogeneous materials, conventional techniques can no longer meet the requirements for such sample preparation. This work focuses on the heterogeneous characteristics of lithium battery electrode materials. By improving the deposition process, optimizing thinning technique, and incorporating stepwise blowing measure, an efficient TEM sample preparation of selected heterogeneous regions is achieved. Such FIB-based preparation method for heterogeneous TEM samples can be extended to a wide range of heterogeneous material systems, thereby assisting scientific innovation and talent cultivation.