This is a multi-center, randomized, double-blind, placebo-controlled study. Study subjects are class III, IV, V, III+V, IV+V lupus nephritis patients, according to ISN/RPS 2003 classification of LN, with active lesion needing corticosteroid in combination with immunosuppressant therapy. Subjects who meet the eligibility criteria during screening will be randomized to 1 of 3 treatment groups in a 1:1:1 ratio: 25mg bid artesunate, 50mg bid artesunate or placebo plus standard of care (prednisone plus mycophenolate mofetil ［MMF］) for 6 month.