Objective:To study the relationship between plasma homocysteine level in pregnant women and premature delivery.Methods:Plasma homocysteine levels in 60 aborted women of 28~34 gestational weeks(case group) and 30 normal pregnant women of 31~34 gestational weeks(study group) were detected by high performance liquid chromatography with fluorescence detection,case-control study was adopted,the correlation between plasma homocysteine level and premature delivery was analyzed by Logistic regression analysis.Results:The plasma homocysteine level in case group was(7.56±2.97) μmol/L,which was significantly higher than that in control group [(5.96±2.54) μmol/L](P=0.013);the increase of plasma homocysteine level in case group didn't elevate the risk of premature delivery except confounding factors,the increase of plasma homocysteine level elevated the opportunity of small for gestational age infant(SGA),especially plasma homocysteine level≥11.0 μmol/L(χ2=8.597,P=0.003);but the incidence of other complications of preterm infants didn't increase.Conclusion:The increase of plasma homocysteine level of pregnant women don't elevate the risk of premature delivery,but increase the delivering rate of SGA.