Objective · To identify the relationship between the estimated fetal weight (EFW) discordance and birth weight (BW) discordance, and evaluate the accuracy of ultrasonography in predicting birth weight discordance (ΔBW) of twin pregnancy. Methods · The ultrasound was used to detect the growth of twins at different gestational weeks and the data were analyzed to compare the difference between EFW discordance (ΔEFW) and ΔBW. Results · About 15.9 percent of twins (totally 277 cases) had severe ΔBW (ΔBW ≥20%) in our study, and the percentages of dichorionic-diamniotic twin (DCDA) and monochorionic-diamniotic twin (MCDA) were 68.2% and 31.8%, respectively (P>0.01). Compared with ΔEFW in other gestational weeks, ΔEFW last time before parturition was most consistent of ΔBW. Furthermore, the negative predictive value of MCDA was highest (94%) at 22–24 gestational weeks. Conclusion · Twin ΔBW was relatively better predicted by ΔEFW last time before parturition. Twin pregnancy without severe ΔEFW (ΔEFW<20%), especially MCDA with ΔEFW<20% at 22–24 weeks, had low probability of selective intrauterine growth restriction in the future.