Aims. This study is designed to explore the effect of compound Danshen injection combined with magnesium sulfate on TNF-α, NO, oxidative stress, and therapeutic efficacy in severe preeclampsia (S-PE). Methods. Sixty S-PE patients were placed into the control group and the therapy group, randomly. The control group was under the treatment of magnesium sulfate, and the therapy group was under the treatment of compound Danshen injection with magnesium sulfate. After treatment, the therapeutic efficacy of the two groups was comparatively analyzed. Results. 7 days after treatment, DBP, SBP, and 24 h urinary protein were sharply lower than those before treatment. The 24 h urinary protein was notably lower in the therapy group. After treatment, the expression level of TNF-α in both groups was notably higher than before treatment, while NO level was higher than that before treatment. Furthermore, D-D level in two groups was dramatically decreased compared to that before treatment. Moreover, Fib, PT, and APTT in two groups showed statistically significant differences after 7 days. The contents of ALT, AST, BUN, and Scr in therapy group were notably lower than those in control group. Conclusion. Our results indicated that compound Danshen injection could improve renal function, blood hypercoagulability, and oxidative stress level and had a better therapeutic effect on S-PE.