Objective To recapitulate the clinical traits of conjunctiva-corneal carcinoma in situ with microinvasion,and explore the early diagnosis and precise therapeutic methods.Methods The clinical features,diagnosis,surgical methods and follow-up results of a hospitalized patient with keratoconjunctival in situ carcinoma with microinvasion were retrospectively analyzed and related literature was consulted.Results Surgical resection of the tumor and 2 mm marginal tissue outside the edge of the tumor was performed.Fresh corneal lamellar grafts were used to treat the disease.After 2 years of follow-up,the operation was effective and no recurrence was found.Conclusion Early diagnosis plays an important role in improving the prognosis of keratoconjunctival carcinoma in situ with microinvasion and preventing recurrence.For patients with keratoconjunctival carcinoma in situ acompanied with microinvasion,we have to expand the surgical resection of the tumor (≥2 mm at the edge of the tumor),and follow-up at regular intervals,if necessary,supplemented with chemotherapy or anti-metabolic treatment.