The main objective is to evaluate the effectiveness of Rituximab monotherapy versus steroid therapy on children with new-onset nephrotic syndrome within the 52-week follow-up.

Nephrotic syndrome(NS) -------the most common glomerular disease in children. Steroid, as the mainstream therapy for decades, many patients suffer from adverse effects of it, such as growth impacted, fat, and glaucoma.There is a urgent need for Steroid-sparing therapy. Rituximab, as a chemical monoclonal antibody against the cluster of differentiation antigen 20(CD20), has proved to be effective in patients with frequent-relapse/steroid-dependent NS. It has also been reported to be effective in six adult patients with new-onset NS. Rituximab mono-therapy in new-onset pediatric NS patients is still unclear.

Inclusion Criteria:

1. New-onset idiopathic nephrotic syndrome
2. Glomerular filtration rate (eGFR) ≥90 ml/min per 1.73 m2 at study entry.

Exclusion Criteria:

1. Glomerular hematuria: Urine red blood cell counts≥ 10/high power field(HP), ≥ 3 times within 2 weeks;
2. Continuous hypocomplementaemia(< 0.9g/L) ;
3. Repeated or persistent Hypertension(systolic and/or diastolic blood pressures measured greater than the 95th percent of blood pressure in children matching sex, age and height ≥3 different time points)
4. Diagnosis of secondary NS, such as secondary to Systemic Lupus Erythematosus, Immunoglobulin A Vasculitis(IgAV), diabetes, Hepatitis B virus(HBV) infection, etc.
5. Complicated with other kidney diseases, such as multiple renal cysts, ANCA vasculitis, urinary system abnormalities, etc;
6. With a family history of nephrotic syndrome, chronic glomerulonephritis, uremia, or other kidney diseases;
7. Other monogenic genetic diseases known as the effect the condition of nephrotic syndromes, such as Wilms' tumor 1(WT1), NPHS2, LAMB2, PLCE1, etc.
8. Congenital or acquired immunodeficiency, or patients with active tuberculosis, active Epstein-Barr virus and cytomegalovirus(CMV), acute hepatitis B, hepatitis C, HIV infection, deep fungal infection or other active infections.
9. Laboratory indicators were abnormal, such as moderate or severe neutropenia(≤1000/μL)， moderate or severe anemia(hemoglobin<9.0g/dL), Thrombocytopenia (platelet count<100* 10^12/L) or with abnormal hepatic function (Alaninetransaminase(ALT), aspartate Aminotransferase(AST) or bilirubin >2.5*upper limit of normal value and continue to increase for 2 weeks);
10. Steroid or immunosuppressive medicine for other diseases within 3 months, such as cyclophosphamide, cyclosporine, tacrolimus, mycophenolate mofetil, tripterygium wilfordii, etc.
11. With tumor, severe cardiac failure, severe hepatologic diseases, hematological diseases, or other severe system diseases.
12. Patients who are known to be allergic to rituximab;
13. History of transplantation, excluding cornea or hair transplantation;
14. The attenuated live vaccine was inoculated within 1 month before enrollment;
15. Patients who participated in other clinical trials within three months before enrollment;
16. Patients are not suitable for inclusion in the trial by any investigator.