Objective To investigate the effect of preventive nursing based on quantitative assessment strategy in severe gestational hypertension syndrome. Methods A total of 84 patients with severe gestational hypertension syndrome who were diagnosed and treated in our hospital from January 2020 to October 2021 were enrolled as subjects, and according to the difference in nursing pattern after admission, they were divided into control group and observation group, with 42 patients in each group. The patients in the control group were given basic nursing, and those in the observation group were given preventive nursing based on quantitative assessment strategy. The two groups were compared in terms of observation results after nursing. Results Compared with the control group, the observation group had significantly lower systolic pressure (138.34±2.32 mmHg) and diastolic pressure (89.45±2.13 mmHg) after nursing (P<0.05), as well as a significantly lower incidence rate of complications (2.38%) (P<0.05). Conclusion Preventive nursing based on quantitative assessment strategy has a marked effect in patients with severe gestational hypertension syndrome and can effectively prevent complications while maintaining stable blood pressure, and therefore, it is highly feasible in clinical practice.