AIM:To discuss the anterior chamber inflammatory response and influence degree after medial rectus muscle and lateral rectus muscle respectively or simultaneously being transected.  METHODS:Retrospective analysis in 52 cases (60 eyes) horizontal strabismus patients who should be operated on medial and lateral rectus muscle surgery. They were divided into two groups, a single horizontal rectus muscle was cut in one eye in group A of 30 eyes; medial and lateral rectus muscle were cut in one eye in group B of 30 eyes. All the eyes were examined preoperatively and 1 day postoperatively with FM - 600 type laser flare cell meter (LFCM). The degree of anterior chamber inflammation was determinated. All aqueous flare data of measured eyes were collected and analysed with SPSS 11.5.  RESULTS:The results of preoperation and postopera-tion showed that no significant difference was observed in group A (P>0.05), but the anterior chamber inflammation changes were different significantly in group B (P<0.05 ). The mean of anterior chamber inflammation was still within the normal range in group B after the first day postoperatively. CONCLUSION:Surgery on one horizontal rectus muscle in one eye can not cause changes of anterior chamber inflammation.The anterior ciliary arteries are injuried after two horizontal rectus muscles are transected simultaneously, which can lead to dysfunction on its supply area: the iris and ciliary body. So a mild inflammation in anterior chamber occurred. The compensation of collateral circulation can prevent occurrence of serious anterior segment ischemia after two horizontal rectus muscles are transected simultaneously.