Aim To investigate the change and significance of serum hydrogen sulfide levels in rats with pregnancy-induced hypertension syndrome （PIHS）. Methods Thirty two adult female Wistar rats were randomly divided into normal control group, normal pregnant group, PIHS group and PIHS + sodium hydrosulfide （NaHS） group. The pregnant rats were treated with nitric oxide synthase inhibitor L-nitro-arginine methylester （L-NAME） ［250 mg/（kg·d）］ by intraperitoneal injection to induce hypertension. The extrogenous sodium hydrosulfide （H₂S） donator NaHS （56 μmol/kg） was used in the experiment. Systolic blood pressure （SBP） of rat was measured by use of tail-cuff. The level of H₂S in serum was detected by spectrophotometry. The levels of urine protein, blood creatinine （BCr） and blood urea nitrogen （BUN） were measured by automatic biochemistry analyzer. The length and weight of fetal rat, weight of placenta and head of fetal rat were measured. Results Compared with the normal pregnant group, SBP, urine protein, BCr and BUN were singificantly increased in PIHS group. The fetal rats in the uterus were hypoevolutism and the length and weight of fetal rat, weight of placenta and head of fetal rat were singificantly decreased in PIHS group compared with the normal pregnant group. The levels of H₂S in serum were singificantly decreased from day tenth of pregnancy to start in