Objective：To explore the predictive value of ficolin（FCN）2 and mannose - binding lectin - associated serine protease （MASP）1 in the risk stratification of IgA nephropathy，and to assess their potential application in the Nanjing IgA nephropathy risk stratification system（NJIgAN-RSS）. Methods：A total of 51 patients with primary IgA nephropathy confirmed by renal biopsy and 20 healthy controls were enrolled. Serum levels of FCN2 and MASP1 were measured by enzyme -linked immunosorbent assay（ELISA）. Based on the NJIgAN - RSS，patients were divided into a low - risk group（RSS 0- 1）and a moderate - high - risk group（RSS 2- 4）. Correlation analyses were conducted to evaluate the relationships between FCN2，MASP1，and various clinical and pathological indicators. Additionally，the predictive value of these biomarkers in the risk stratification of IgA nephropathy was explored. Results： Serum FCN2 levels in patients with IgA nephropathy were significantly elevated compared to those in healthy controls. Furthermore， FCN2 levels exhibited a positive correlation with the urine protein-to-creatinine ratio（UPCR），24 h urine protein excretion（UPE），and endocapillary hypercellularity. Additionally，MASP1 levels demonstrated a positive correlation with UPCR，UPE，and urinary red blood cells. Notably，both eGFR and serum FCN2 were identified as independent predictors for the medium - to - high - risk group in IgA nephropathy. Conclusion：Serum FCN2 possesses a high predictive value for prognostic risk stratification in IgA nephropathy.