Elucidating the boundary of tumors is significant for cancer diagnosis and cure. In this work, our group proposed an innovative method for the diagnostic analysis of clinical lung cancer tissues based on label-free imaging. The heterogeneity of multielements and molecular fragments was obtained simultaneously for three types of clinical samples containing different proportions of cancerous tissue by laser-induced breakdown spectroscopy (LIBS) imaging. The results of elemental imaging mainly reveal the differential distribution of Ca, Mg, Na, and Cu in cancer tissues, paracancer tissues, and normal tissues. In particular, for the first time, we discovered the spatial heterogeneity of molecular fragments between tumor and necrosis regions. The tumor regions produced more CN molecules during laser ablation, while almost no C-2 molecules were produced. Further spatial segmentation shows the clearer boundary of the tumor and necrotic areas in cancer tissues and paracancer tissues. Our work indicates that the heterogeneity of multielements and molecular fragments has great potential as diagnostic biomarkers of tumors boundary.