Objective  To investigate the correlation between the polymorphism of 5,10-methylenetetrahydrofolate reductase (MTHFR) gene rs1801131 and hypertensive disorders complicating pregnancy(HDCP) in Qinghai Han nationality.     Methods  The polymorphism of MTHFR rs1801131 in 120 pregnant women with HDCP (HDCP group) and 120 normal pregnant women (control group) were detected by restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) and verified by sequencing.     Results  The frequencies of AA, AC, and CC genotype of MTHFR gene in the HDCP group were 56.67%, 32.50%, and 10.83% respectively, and those in the control group were 74.17%, 23.33% and 2.50% respectively (P<0.05), the distribution of genotype was different significantly between the two groups). The frequency of AA genotype of HDCP group (56.67%) was lower than that of control group (74.17%, P<0.05), the frequency of CC genotype of HDCP group (10.83%) was higher than that of control group (2.50%, P<0.05), while there was no significant difference in the frequency of AC genotype between HDCP group and control group (P<0.05). The frequency distribution of alleles A and C of MTHFR rs1801131 polymorphism was significantly different between the HDCP group and the control group (P<0.001), and the frequency of allele C in the HDCP group was significantly higher than that in the control group (χ2=12.229,  OR=1.574, 95%  CI=1.181-2.099, P<0.001).     Conclusion  The polymorphism of MTHFR rs1801131 is related to the occurrence of HDCP in Qinghai Han population. The C gene might be the susceptibility gene of HDCP, and CC genotype might be the susceptibility genotype of HDCP.