Abstract: Objective To investigate the clonal growth behavior and analyze the proliferation characteristics of cancer cells. Methods Human breast cancer cell line MCF-7, human colorectal cancer cell line SW480 and human gastric cancer cell line SGC7901 were selected to investigate the morphological features of cell clone. Quantum dots-based molecular targeting imaging techniques were applied to mark the cytoplasm by quantum dots as green, and cell nucleus Ki67 as yellow or red, to investigate the clone formation rate, cell morphology, dispersion and the expression and distribution of Ki67 in cancer cells. Results From the cell clone formation assay, MCF-7, SW480 and SGC7901 cells formed clones on d6, d8 and d12 of cell culture period, respectively. All of these three types of cells had obvious atypia of morphological features, large nuclear-cytoplasm ratios, and conspicuous irregular mitotic figures. The cells around the clones formed multiple pseudopodium. And in part of the above clones, cancer cells at the borderline were separated from the central cell clusters or presented dispersion. With quantum dots-based molecular targeting imaging techniques, the cells with strong Ki67 expression were mainly distributed around the clones, or concentrated on one side of the clones. Conclusion Ki67 is widely expressed in MCF-7, SW480 and SGC7901 cell clones, with strong expression around the clones, or concentrated on one side. And cancer cell clones present obviously asymmetric growth behavior.