Objective: To evaluate the effect and safety of Kuanxiong Aerosol (宽胸气雾剂, KA) on patients with angina pectoris. Methods: Block randomization was performed to randomly allocate 750 patients into KA (376 cases) and control groups (374 cases). During an angina attack, the KA group received 3 consecutive sublingual sprays of KA (0.6 mL per spray). The control group received 1 sublingual nitroglycerin tablet (NT, 0.5 mg/tablet). Log-rank tests and Kaplan-Meier estimations were used to estimate the angina remission rates at 6 time-points after treatment (1, 2, 3, 4, 5, and ＞5 min). Logistic regression analysis was performed to observe the factors influencing the rate of effective angina remission, and the remission rates and incidences of adverse reactions were compared for different Canadian Cardiovascular Society (CCS) classes of angina. Results: The 5-min remission rates in the KA and control groups were not significantly different (94.41％ vs. 90.64％, P＞0.05). The angina CCS class significantly influenced the rate of remission (95％ confidence interval = 0.483–0.740, P＜0.01). In the CCS subgroup analysis, the 3- and 5-min remission rates for KA and NT were similar in the CCSⅠ and Ⅳ subgroups (P＞0.05), while they were significantly better for KA in the CCSⅡ and Ⅲ subgroups (P＜0.05 or P＜0.01). Furthermore, the incidence of adverse reactions was significantly lower in the KA group than in the control group for the CCSⅡ and Ⅲ subgroups (9.29％ vs. 26.22％, 10.13％ vs. 20.88％, P＜0.05 or P＜0.01). Conclusions: KA is not inferior to NT in the remission of angina. Furthermore, in CCSⅡ and Ⅲ patients, KA is superior to NT, with a lower incidence of adverse reactions. (Registration No. ChiCTRIPR- 15007204)