Abstract: Objective Exploring the difference of residual placental blood volume between delayed cord clamping and early cord clamping, to avoid the potential harm on newborns by too early to cut the cord.Methods From Mar. to Jun. in 2015 in Haikou maternal and child health hospital, 403 cases vaginal birth with vertical term single normal baby were enrolled and randomized to two groups, study group (n=202) adapted delaying cord clamping until the pulsation of the cord artery ceased, control group (n=201) adapted cutting the cord within 60 second. Residue blood in the umbilical cord was collected from the placental size in both groups.Results Residual placental blood volume in study group(14. 12 ± 12. 40) m L was less than that in control group(69. 049 ±50. 02) m L (t=15. 112, P< 0. 01); the peak level of bilirubin(11. 84 ± 3. 24) mg/d1 in study group was lower than that in control group(16. 31 ± 1. 93) mg/d1 (t=4. 900 P< 0. 01); postpartum blood loss(160. 24 ± 72. 90) m Lin study group was less than that in control group(187. 77 ± 104. 62) m L (t=3. 063, P=0. 002), and the differences were all statistically significant.Conclusions Delayed cord clamping until the secession of the umbilical artery pulsation reduces the residual placental blood volume, that suggests more placental transfusion to the newborns which is evidenced with clinical practical values.