Purpose: The aim of this study was to investigate the efficacy and safety of tratinterol hydrochloride in bronchial asthma (BA) treatment.Methods: Patients enrolled in this study were distributed randomly into a treatment group (tratinterol hydrochloride) and an active control group (procaterol hydrochloride) and were treated for 2 weeks after running-in. The end points were changes in pulmonary function and clinical symptoms after administration. Safety indices were physical examinations, laboratory testing and spontaneous reporting.Findings: We enrolled 732 subjects, −365 in the treatment group and 367 in the active control group. Forced expiratory volume (FEV1), significantly increased in both group after treatment (P