Ocular surface squamous neoplasia(OSSN)is a type of ocular surface tumor, which is difficult to diagnose because of its low incidence is low and it is easy to be confused with pterygium. In recent years, the improvement of various diagnostic techniques and the extensive application of interferon(IFN)to OSSN therapy have greatly reduced the recurrence rate, and the diagnostic and therapeutic methods of OSSN tend to be diversified. Understanding the current causes of OSSN and the ways of treatment can better guide the OSSN study.