Objective To evaluate the efficacy and safety of domestic ambroxol hydrochloride injection in the treatment of lower respiratory tract infection. Methods A total of 120 patients with respiratory tract infections were included and randomized into the treatment group (ambroxol hydrochloride injection 30mg, iv, q12h) and the control group (mucosolvan ampoule 30mg, iv, q12h). The duration of treatment was 6 days. Results 118 patients completed the trial, 59 in each group. From Day 1 to Day 6, the severity scores of cough, sputum amount, difficulty in expectoration and rales were similar between the two groups (Pgt;0.05), but a significant difference was observed in the nature of sputum (Plt;0.05). The total effective rates of the treatment group and the control group were 96.6% (FAS analysis and PP analysis) or 93.3% (FAS analysis), and 94.9% (PP analysis), respectively. There was no significant difference between the two groups (Pgt;0.05). The incidence of adverse effects was comparable between the two groups (1.7% vs. 0%, Pgt;0.05), and no severe adverse effect was observed. Conclusion The efficacy of domestic ambroxol hydrochloride injection in the treatment of lower respiratory infection was equal to that of mucosolvan ampoule, and it can even further improve the nature of sputum. Ambroxol hydrochloride was as safe as mucosolvan ampoule.