Objective To investigate the spontaneous skin carcinoma of Japanese big-ear rabbit. Methods Pathological histology HE staining and electron microscope were adopted.Results Under optical microscope, the carcinoma cells arranged in nest dwelling pattern with empty and understained cytoplasm. Big nuclei and pathologic mitosis could also be seen often. Under electron microscope, the carcinoma cells arranged tightly with desmosemes between some cells. Glycogen and tonofibril in cytoplasm were common,with little other organelle seen. Nuclei of carcinoma cells were big and various in size with irregular karyomorphism.Conclusion The skin carcinoma is spoutaneous sweat gland carcinoma.