Disclosed are a diglycosylated benzophenoxazine photosensitizer, and a preparation method and use thereof. The present invention greatly improves the enriched concentration of the photosensitizer in tumor cells by taking full advantage of the enhanced uptake and enhanced glycolysis of carbohydrates by tumor cells and the glycosylation of a selenium-containing benzophenoxazine compound, thereby improving the targeting of a diglycosylated benzophenoxazine photosensitizer involved in the present invention in the treatment of cutaneous tumors and also significantly decreasing the toxic and side effects of the photodynamic therapy. The present invention can efficiently and rapidly inhibit the proliferation of cells of cutaneous squamous cell carcinoma and essentially cause no damage to normal cells.