Abstract: Objective To explore the role of probiotic supplements in improving the immune function in infants with meconium aspiration syndrome(MAS). Methods Total 49 newborns with MAS in our neonatology department between January,2013 and January,2015 were randomly divided into treatment group(Ⅰ group) and observation group(Ⅱ group),while 34 healthy term infants during the same period were recruited as contrast group (Ⅲ group).During the follow up,the levels of blood IgG,IgM,IgA and tumor necrosis factor-α(TNF-α) were tested at 1,3,6 and 12 months of age.The patients with wheeze for 4 times or over were counted,and the results were analyzed. Results In 1 month age, the IgM content of blood in different groups had significant differences (P<0.05),as follows Ⅰgroup (0.057±0.049)g/L, Ⅱgroup(0.059±0.013)g/L,Ⅲgroup(0.030±0.037)g/L.In 6 month age, the IgG content of blood in three groups were as follows(6.233±1.213)g/L,(5.230±1.158)g/L,(7.238±1.612)g/L, the IgA content of blood in three groups were as follows (0.423±0.258)g/L,(0.332±0.191)g/L,(0.512±0.398)g/L;the TNF-α content of blood in three groups were as follows(2.006±1.129)ng/ml,(2.520±1.188)ng/ml,(1.191±0.319)ng/ml,all of them had significant differences(P<0.05)。In 12 month age,the IgG content of blood in three groups were as follows(8.332±1.782)g/L,(7.150±1.238)g/L,(8.672±1.912)g/L;the IgM content of blood in three groups were as follows(1.487±0.533)g/L,(1.058±0.390)g/L,(1.548±0.853)g/L;the IgA content of blood in three groups were as follows(0.423±0.258)g/L,(0.332±0.191)g/L,(0.512±0.398)g/L;the TNF-α content of blood in three groups were as follows(1.289±0.293)ng/ml,(2.127±1.276)ng/ml,(1.223±0.363)ng/ml,all of them had significant differences(P<0.05).The number of breathing which equal or greater than 4 times in three groups had no significant difference(P>0.05),as follows Ⅰgroup 0 case(0/29),group 3 cases(3/20),Ⅲ group 1 case(1/34),but the incidence rate of breathing Ⅲ group was obviously higher than that of groupⅠand Ⅱ. Conclusion Meconium aspiration syndrome infants who suppled probiotics had some improvement on immune function,and had the potential to reduce the risk of develiping asthma.>