Objective To study the changes and clinical significance of serum matrix metalloproteinase-9(MMP-9) ,tissue inhibi-tor of metalloproteinase-1(TIMP-1) and vascular endothelial growth factor (VEGF) in infants with early wheezing .Methods Ser-um levels of MMP-9 ,TIMP-1 and VEGF in 116 infants with early wheezing(wheeling group)and 36 healthy infant (control group) were detected by using ELISA .Results Serum levels of MMP-9 ,TIMP-1 and VEGF in wheeling group were significantly higher than those in control group(P<0 .05);In wheeling group ,there was a linear relationship between the level of MMP-9 and VEGF ;the ratio of MMP-9/TIMP-1 was significantly lower in wheeling groups than in control group(P<0 .05) .Conclusion The infants with early wheezing have the dangerous of airway remodeling .Detection of serum levels of MMP-9 ,TIMP-1 and VEGF is of a cer-tain significance for intervention therapy to wheezing infants as early as possible .