Abstract: Objective To study the expression of C-kit protein in primary mucosal malignant melanoma（PMMM）and its relation with invasion and metastasis of PMMM. Methods Clinical data about 18 PMMM patients admitted to our hospital from January 2003 to December 2009 with their diagnosis confirmed by histopathology and immunohistochemistry were retrospectively analyzed.Expression of C-kit protein was detected with the immunohistochemistry S-P method.Effect of common clinical and pathological factors for PMMM on its prognosis was analyzed and evaluated. Results The expression of C-kit protein was not related with the clinical and pathological factors for PMMM,including age,gender,prognostic surviving state of the patients and focal diameter of PMMM,but significantly related with lymphatic metastasis of PMMM（P＜0.05）. Conclusion Expression of C-kit protein is closely related with the lymphatic metastasis and prognosis of PMMM while loss of C-kit protein expression is closely related with the occurrence of PMMM and its abnormal proliferation.