Purpose: To observe and compare the efficacy of timolol eye drops in sequential treatment of acute angle-closure crisis (AACC). Methods: In this prospective, randomized, double-blind case-control study, patients diagnosed with AACC at the Affiliated Hospital of Hebei University from April 2021 to October 2023 were continuously enrolled. The patient data were collected and randomly divided into timolol group (group A) and placebo group (group B). All patients were sequentially treated with drug therapy, anterior chamber paracentesis, and argon laser peripheral iridoplasty. The primary outcomes were decreased intraocular pressure (IOP), success rate, and treatment time. Findings: At 2 hours, 4 hours, and 6 hours after the start of treatment, the reduction in IOP in group A was 13.87 +/- 13.85 mm Hg, 28.42 +/- 12.87 mm Hg, and 35.69 +/- 8.51 mm Hg, respectively, and the number of controlled eyes was 23 (29.87%), 51 (66.23%), and 71 (92.20%), respectively. The reduction in IOP in group B was 15.88 +/- 14.95 mm Hg, 28.17 +/- 13.63 mm Hg, and 33.90 +/- 13.59 mm Hg, respectively, and the number of controlled eyes was 30 (36.59%), 58 (70.73%), and 75 (91.46%) eyes, respectively. Among patients whose crises were relieved, the times for AACC relief were 3.29 +/- 1.31 hours in group A and 3.38 +/- 1.34 hours in group B. There were no significant differences in IOP reduction, numbers of eyes remission, and times for AACC relief between the 2 groups at each point of sequential treatment ( P > 0.05). Implications: In the sequential treatment of AACC, timolol is not helpful to improve the success rate of treatment.