Objective To study the correlation between maternal hemoglobin level during pregnancy and perinatal outcome of twins. Methods The clinical data of pregnant women with twin pregnancies who underwent prenatal examination and delivery from May 2015 to November 2022 were retrospectively analyzed. Results A total of 2524 women with twin pregnancies were included. The mean hemoglobin (Hb) in early pregnancy was (118.0±10.9) g/L, higher than that in late pregnancy, (116.6±13.0) g/L, and the difference was statistically significant (P<0.01). The incidence of iron deficiency anemia was 22.1% in early pregnancy and 27.7% in late pregnancy. High Hb (Hb>130g/L) might be associated with an increased risk of neonatal asphyxia (AOR=2.10, 95%CI: 1.13-3.87) and small for gestational age infants (AOR=1.39, 95%CI: 1.09-1.98). Moderate to severe anemia during early pregnancy might increase the risk of small for gestational age infants (AOR=2.61, 95%CI: 1.52-4.49). Mild anemia in early pregnancy did not increase the risk of perinatal adverse outcomes. If mild anemia in early pregnancy was corrected in late pregnancy, the risk of neonatal asphyxia (AOR=0.27, 95%CI: 0.07-0.97) might be reduced compared with those with persistent anemia, and the birth weight of larger fetuses in twins is higher (P<0.05). Conclusions Compared with those with persistent anemia in twin pregnancies, the risk of neonatal asphyxia was reduced in those whose anemia was corrected in late pregnancy. Therefore, the necessity of iron supplementation and Hb monitoring for anemic pregnant women with twin pregnancies should be emphasized.