Background: IgA vasculitis nephritis (IgAVN) is the most common secondary glomerulonephritis in children. Persistent hematuria or proteinuria increases the risk of chronic kidney injury . Huaiqihuang (HQH) granules are widely used as an adjunctive therapy in Asia, yet high-quality real-world evidence based on causal inference is still limited. Objective: To assess the efficacy of Huaiqihuang granules in shortening remission time in pediatric IgAVN, and to explore clinical features related to treatment response using machine learning. Methods: This retrospective real-world study included 779 children with IgAVN, divided into isolated hematuria (n=154) and proteinuria (n=625) groups. Patients received HQH plus conventional therapy or conventional therapy alone. 1:1 propensity score matching was performed in each subgroup to balance baseline characteristics. Remission time was analyzed by Kaplan–Meier and Cox regression. Multivariable analysis identified independent predictors, and an XGBoost model was built to recognize responsive phenotypes. Results: After matching, baseline characteristics were well balanced. HQH significantly shortened median remission time in both groups (P