Objective To explore the clinical significances of pulmonary function test in children with asthma or cough variant asthma (CVA). Methods A total of 80 patients who were diagnosed asthma or CVA at outpatient of Hebei Children's Hospital were selected from May to November in 2010.They had been divided into three groups.Group A for 33 patients with acute asthma,whose average age was (7.96±2.12) years old;group B for 27 patients with asthma remission phase,whose average age was (7.97±1.91) years old;and group C for 20 patients with cough variant asthma,average age was (8.03±2.18) years old.30 children from healthy children were also randomly selected as group D,whose average age was (8.58±2.11) years old.All children were tested by the pulmonary function machine.There were seven pulmonary function indexes,such as forced vital capacity (FVC),forced expiratory volume in one second (FEV1),peak expiratory flow (PEF),forced expiratory flow after 25% (FEF25),forced expiratory low after 50% (FEF50),forced expiratory flow after 75% (FEF75),maximal mid-expiratory flow (MMEF75/25) and so on. Results All the pulmonary function indexes from group A and B and C were lower than those of group D,except PEF,FEF50,FEF75 of group B and C.Each pulmonary function indexes from group A were much lower than those of group B and C,but there was no significant difference between group B and C. Conclusion Pulmonary function test is important to assess the degree of airway obstruction,diagnose and evaluate severity for children with asthma or CVA.