A prospective, multi-centric, cohort study to observe the efficacy difference between intensive classic DMARDs and Infliximab(IFX) with methotrexate(MTX) treatment in sever rheumatoid arthritis(RA) 28 joints disease activity score>5.1(DAS28>5.1) patients with poor prognostic factors.Primary objective is compare the difference of clinical remission rate between classic DMARDs and Infliximab with MTX treatment in severe RA patients with poor prognostic factors at week 30.