To make an analysis of preventive effects of carteolol hydrochloride on refractive regression for extreme high myopia after LASIK. METHODS: LASIK was performed in 68 cases of 136 eyes with extreme high myopic. All the cases were randomly divided into treatment group and control group. Carteolol hydrochloride was administered topically twice per day to the treatment group from the second week to the end of first month postoperatively. Uncorrected visual acuity(UCVA)，refration，slit-lamp examination，intraocular pressure(IOP)，topography examination and anterior chamber depth(ACD) were examined in these patients and the period of follow-up was 6 months. RESULTS: Three months and 6 months after surgery,there was significant difference of UCVA ≥1.0 and refraction between treatment group and control group(P＜0.05). 1 week,1 month,3 months and 6 months postoperatively the IOP in treatment group and control group were significantly different in different periods(P＜0.02). There was significant difference of ACD between treatment group and control group 1 month after surgery (P＜0.05). There were significant differences of corneal refractive power and posterior corneal Diff value between two groups 3 months and 6 months postoperatively(P＜0.05). CONCLUSION:For extreme high myopia patients using carteolol hydrochloride after LASIK can stabilize the refraction and reduce refractive regression.