OBJECTIVE: To observe the efficacy and safety of tocilizumab against refractory systemic onset juvenile idiopathic arthritis(SoJIA). METHODS: A prospective follow-up study of 16 patients with refractory active SoJIA patients with or with tocilizumab after treatment of clinical disease activity indicators and safety. The ANOVA was used for statistical analysis. RESULTS: After 2 weeks,12 weeks and 52 weeks of treatment,the levels of white blood cells,erythrocyte sedimentation rate and hypersensitive C-reactive protein were significantly decreased,and there were statistically significant differences(F=26.25、145.70、517.96,P<0.05). JADAS27 was significantly decreased after 2 weeks,12 weeks and 52 weeks of treatment with tocilizumab(the score being 23.09±3.46,8.19±2.63,4.25±2.86 and 2.63±1.54),the difference being statistically significant(P<0.05). Some children had adverse reactions,2 cases of skin abnormalities,1 case of white pityriasis,1 case of skin infection;3 cases of liver enzyme abnormalities;2 cases of leukopenia. CONCLUSION: Tocilizumab can improve the condition of children with SoJIA in rapid and obvious way,and medium and longterm security and tolerance was good. The duration of tocilizumab therapy should be carefully assessed.