Inclusion Criteria:  Age 14~65 years, regardless of gender Clinical evaluation and renal biopsy diagnostic for IgA nephropathy, presenting with crescents. Average urinary protein excretion of 0.3~3.5g/24h on two successive examinations. eGFR≥30 ml/min/1.73m2. Willingness to sign an informed consent.  Exclusion Criteria:  Secondary IgAN such as systemic lupus erythematosus, Henoch-Schonlein purpuric nephritis and hepatitis B-associated nephritis, etc. Rapidly progressive nephritic syndrome (crescent formation≥50%). Acute renal failure, including rapidly progressive IgAN. Current or recent (within 30 days) exposure to high-dose of steroids or immunosuppressive therapy (CTX、MMF、CsA、FK506). Date of renal biopsy exceeds more than 30 days. Cirrhosis, chronic active liver disease, and serious liver function damage. History of significant gastrointestinal disorders (e.g. severe chronic diarrhea or active peptic ulcer disease). Any Active systemic infection or history of serious infection within one month. Other major organ system disease (e.g. serious cardiovascular diseases including congestive heart failure , chronic obstructive pulmonary disease, asthma requiring oral steroid treatment or central nervous system diseases). Active tuberculosis Malignant hypertension that is difficult to be controlled by oral drugs. Known allergy, contraindication or intolerance to the steroids. Pregnancy or breast feeding at the time of entry or unwillingness to comply with measures for contraception. Malignant tumors. Excessive drinking or drug abuse. Mental aberrations. Current or recent (within 30 days) exposure to any other investigational drugs. Current use of RAS inhibitors needs to be eluted for at least 1 week before participating in the study.