AIM:To evaluate the therapeutic effect of localized mitomycin C(MMC) applied in operation for treating patients with pterygium. ·METHODS:Totally of 259 patients 279 eyes with pterygium by corneal incursion more than 2mm were received 0.2mg/mL MMC on sclerae for 3 minutes after pterygium resection under microscope. Subsequently,all eyes were treated with tobramycin and dexamethasone eyedrop (qid) and tobramycin and dexamethasone ointment (qn) for 1 week postoperatively. The corneal infiltration,blood vessels and plump degree of pterygium were observed. The follow-up of 12 to 18 months were carried out to all of patients. ·RESULTS:After operation,271 eyes with pterygium were cured,which occupied 97.1%. Recrudescence was found in other 8 eyes with proportion of 2.9%,the patients suffered unilateral pteygium in one eye,unilateral pterygium in both eyes and bilateral pterygia in one eye were 1.8%,2.5%,14.3% respectively. ·CONCLUSION:Localized MMC intraoperatively is an effective treatment for primary pterygium when it only occurred in one eye with low recrudescence and without side-effect. However,the unilateral pterygium in both eyes or bilateral pterygia in one eye are still have high incidences to recur.