Abstract: Objective To detect the abnormal expression of placenta-specific protein 1(PLAC1) of patient with fetal growth restriction(FGR), and discuss its significance. Methods Forty FGR pregnant women who were hospitalized and delivered in Jiaxing Maternal and Child Health Hospital from April 2017 to January 2020 were selected as the FGR group, and 40 normal pregnant women who were hospitalized and delivered during the same period were selected as the control group. The placental thickness, placental mass and neonatal weight were measured. Reverse transcription-polymerase chain reaction(RT-PCR) was used to determine PLAC1 mRNA levels in placenta and peripheral blood. The t-test was used to analyze the differences of the indicators between the two groups. Correlation between indicators was analyzed using Pearson. Results The placental thickness, placental mass and neonatal weight in the FGR group were lower than those in the control group(all P<0.05).The level of PLAC1 mRNA in the placenta of the FGR group(0.47±0.09) were lower than that of the control group(1.00±0.07), t=29.399, P<0.05.The level of PLAC1 mRNA in the peripheral blood of the FGR group(1.54±0.11) was higher than that of the control group(1.00±0.08), t=25.109, P<0.05. The placental PLAC1 mRNA level in FGR pregnant women was positively correlated with placental thickness, placental mass and neonatal weight(all P<0.05). The peripheral blood PLAC1 mRNA level in FGR pregnant women were negatively correlated with placental thickness, placental mass and neonatal weight(all P<0.05).There was negatively correlation between PLAC1 mRNA levels in the placenta and peripheral blood of FGR pregnant women(r=0.602, P<0.001). Conclusion The level of PLAC1 mRNA in placenta and peripheral blood can reflect the severity of FGR.