Abstract: Objective To ascertain the effect of food exchange portion in nutrition intervention on gestational diabetes mellitus(GDM),and provide a theoretical basis for nutrition guidance on GDM and reduction of maternal and neonatal complications. Methods A total of 198 singleton pregnancy women diagnosed with GDM at 24th to 28th pregnant week were selected in Jiangbei District of Ningbo City.Among them,123 patients voluntarily accepted individualized nutrition guidance and were included in the intervention group,while the control group consisted of 75 patients without systematic nutrition intervention.Then the two groups of pregnant women were compared in their maternal complications and pregnancy outcomes. Results Through individualized nutrition guidance and intervention of food exchange portion,fasting glucose and postprandial blood glucose dropped significantly after the treatment in the pregnant women of the intervention group as compared with those in control group.Such differences between the two groups had statistical significance(P<0.05).Pregnancy complications in intervention group such as polyhydramnios,birth rate of macrosomia and neonatal asphyxia were lower than those in control group.Such differences were statistically significant (P<0.05).But the differences between the two groups in premature rupture of membranes,preterm birth,Caesarean section and the incidence of low birth weight did not have statistical significance(P>0.05). Conclusion Timely individualized nutrition of food exchange portion guidance for GDM pregnant women can reduce maternal and neonatal complications and improve pregnancy outcomes.