Abstract: Objective: To study the influence of change of IgA,IgG,IgM and C3 on the immune function of the neonates with hypoxic ischemic encephalopathy(HIE).Methods: Twenty-four cases of neonates HIE and eight controls were concluded in this study.Immuno turbidimetric method was used to detect the serum levels of IgA,IgG,IgM and C3 of the neonates,and the results were compared between the two groups.Results: There was no statistical difference in C3 and IgG(P>0.05),but IgM and IgA were significantly different between the two groups(P<0.01);IgG showed statistical difference between the mild HIE group and the severe HIE group(P<0.01),but there was no significant difference in IgA,IgM and C3(P>0.05).Conclusions: The IgA and IgM levels may decrease in the neonates HIE.HIE is related to IgG to some extent but is not related to C3.