Objective To investigate the clinical efficacy and its security on different kinds of atomization with mucosolvan and chymotrypsin in treating neonatal pneumonia.Methods Seventy-eight neonates who were diagnosed as neonatal pneumonia were divided into treatment group (n =39) and control group (n =39) by random number table method from Jul 2011 to Aug 2013 in our hospital.The control group was treated with chymotrypsin atomization,and the treatment group was treated with compression atomizing to inhale mucosolvan.The treatment effects of two groups were compared.Results Compared with the control group after treatment for 24 h,48 h,72 h,the treatment group had more significant increasing in PaO2,more decreasing in PaCO2 and more significant improvement in oxygenation index.There were statistical significances between the two groups(P ＜ 0.01).The treatment group spent shorter time in remission of symptoms,disappear of signs and hospital stay than that of the control group(P ＜ 0.05).In the treatment group,25 cases were markedly improved,9 cases were effective,5 cases were invalid.The effective rate was 87.2％.In the control group,14 cases were markedly effective,6 cases were effective,19 cases were invalid.The effective rate was 51.3％.The effective rate was significant difference between the two groups (P ＜ 0.01).The adverse drug reactions were not found in the process of treatment for two groups.Conclusion Mucosolvan atomizing inhalation has a better treatment effect than chymotrypsin.It can shorten the course of treatment,and is worth promoting the application.