Abstract: Objective:To investigate the efficacy and safety of tacrolimus combined with methylprednisolone in the treatment of myasthenia gravis.Methods:One hundred patients with myasthenia gravis were randomly divided into the control group and observation group(50 cases each group).The control group and observation group were treated with methylprednisolone and methylprednisolone combined with tacrolimus,respectively.The quantitative myasthenia gravis(QMG) score,activities of daily living(ADL) score,indictors of blood,liver and kidney,total treatment effect,quality of life and adverse reactions between two groups were compared.Results:Before treatment,the differences of the scores of QMG and ADL between two groups were not statistically significant(P>0.05).The scores of QMG and ADL in two groups after treatment were significantly lower and higher than those before treatment respectively(P<0.01),the OMG score in observation group was significantly lower than that in control group after treatment(P<0.01),and the ADL score in observation group was significantly higher than that in control group after treatment(P<0.01).The effective rate in observation group(90.00%) was significantly higher than that in control group(60.00%)(P<0.01).Before treatment,the difference of the score of each dimension of quality of life scale was not statistically significant(P>0.05).The score of each dimension in observation group was significantly lower than that in control group after treatment(P<0.01).After treatment,the differences of the indictors of blood,liver and kidney between two groups were not statistically significant(P>0.05),and the difference of adverse reaction between the observation group(10.00%) and control group(14.00%) was not statistically significant(P>0.05).Conclusions:The clinical efficacy of tacrolimus combined with methylprednisolone in the treatment of myasthenia gravis is obvious,and has high safety.