Objective To explore the instructive role of pulmonary function monitoring in diagnosis and treatment of infants with asthma.Methods Spirometry was used to determine respiratory physiologic parameters respectively both in period of acute episode and remission.Results 45 cases were found to be with obstructive ventilation dysfunction out of 62 cases with mild to moderate acute episode,while 10 cases out of 15 with severe acute episode were found to be with mixed ventilation dysfunction,15 cases in period of remission showed mild to moderate obstructive ventilation dysunction.Conclusion Tidal breath pulmonary function monitoring may play a very important role in judging the state of asthma,deciding curative effects and following up.