Objective:To investigate the changes of pulmonary artery pressure(PAP) and right ventricular function in the infants with acute asthma. Methods: One hundred infants during the acute stage of asthmatic disease as observation group(including 23 severe cases and 77 mild cases) and one hundred healthy infants as control group were chosen in this study from October 2009 to January 2012. PAP,right ventricular ejection fraction(RVEF),pulmonary vascular resistance(PVR),right ventricular ejection time(RVET),acceleration time(AT) and Tei were measured as previously reported using echocardiography,and blood gas was analyzed simultaneously. The infants in observation group were conventionally treated with cardiac diuretics and calcium antagonists in order to reduce pulmonary artery pressure and strengthen the heart function. Results: The incidences of pulmonary hypertension was 34%(34/100) in the observation group,23 cases with severe asthma and 11 cases with mild asthma, and 2%(2/100) in the control group. The difference of the incidences of pulmonary hypertension between two groups was significant(P < 0.05),and the incidence of pulmonary hypertension in severe cases was significantly higher than that in mild cases(P < 0.05). PaO2 and SaO2 in the infants with pulmonary hypertension were lower than those who without pulmonary hypertension (P < 0.05). Compared with the control group,RVET and AT decreased,PAP and PVR increased significantly in the observation group (P < 0.05). Compared with mild cases,RVET and AT decreased,PAP and PVR increased significantly in severe cases(P < 0.05). Conclusion: Pulmonary hypertension and declined right ventricular function emerged in the infants with acute stage of asthmatic disease,and aggravated with the disease progress.