Abstract：Objective：To investigate the effect of safflower injection on nitric oxide(NO)，Ca2 +，malondialdehyde(MDA) and superoxide dismutase(SOD) in serum in model mice with dysmenorrhea. Methods：A total of 24 female non- pregnant ICR mice were randomly divided into the blank group，the model group and the safflower group. Except for the blank group， the other two groups were given estrogen combined with oxytocin to induce the primary dysmenorrhea models. The blank group and the model group were given saline，and the safflower group was given safflower injection. All groups were treated for seven days. The contents of NO，Ca2+，MDA and SOD in serum of mice were measured，the uterus was weighed，and the uterine coefficient was calculated. The uterine sections were prepared to observe the gland hyperplasia，inflammatory cell infiltration and intestinal metaplasia. Results： Compared with those in the control group， the writhing times， the uterine coefficient and the levels of Ca2 + and MDA in serum in the model group were increased(P＜0.01，P＜0.05)；the content of NO in serum was decreased(P＜0.05)； the level of SOD was decreased， but there was no significance in the difference.Compared with those in the model group，the writhing times，uterine coefficient and the levels of Ca2+ and MDA in serum in the safflower group were decreased(P＜0.01，P＜0.05)；the content of NO in serum was increased(P＜0.05)；the level of SOD was increased， but there was no significance in the difference. Conclusion： Safflower injectioncan can alleviate dysmenorrhea in mice，whose mechanism may be related to increasing NO in blood as well as decreasing the contents of MDA and Ca2+.