Background: To investigate the associations of adjusting gestational weight gain rate (GWGr) with maternal and neonatal outcomes. Methods: We analyzed 6235 singleton pregnancies among women with normal pre-pregnancy body mass index at two medical centers in China during 2016~2018 to figure out whether pregnancy outcomes could be improved by adjusting GWGr timely when the first-trimester weight gain rate (GWGr-1) and/or the second-trimester weight gain rate (GWGr-2) were inappropriate. Results: When GWGr-1 was excessive, excessive GWGr during the second and third trimesters of pregnancy (late GWGr) was associated with a higher risk of cesarean section (CS), postpartum hemorrhage (PPH), obstructed and prolonged labor and large for gestational age (LGA), and inadequate late GWGr was associated with a lower prevalence of CS and hypertensive disorders of pregnancy (HDP). In pregnancies with inadequate GWGr-1, excessive late GWGr was related to a higher rate of CS, LGA and HDP. Among women with adequate GWGr-1, excessive GWGr in the third trimester (GWGr-3) was positively associated with CS, HDP, and obstruction and prolongation of labor if their GWGr-2 was excessive, and excessive GWGr-3 was associated with a higher risk of CS even though tFheir GWGr-2 was inadequate. Conclusions: Prompt control of GWGr, even during late pregnancy, was beneficial to improving pregnancy outcomes.