Abstract: Pediatric allergic diseases, including asthma, atopic dermatitis, and allergic rhinitis, have increasingly become a global public health concern, with T helper 2 (Th2)-type inflammatory responses serving as the core pathological basis. Currently, a variety of targeted biological agents, including upstream anti-thymic stromal lymphopoietin (TSLP) agents and downstream anti-IgE, anti-IL-5, and anti-IL-4Rα agents, have been approved for use in children and can effectively improve the clinical symptoms of refractory pediatric allergic diseases. Compared with traditional symptomatic drugs, novel targeted biological agents not only enable stratified and precise medication based on Th2 inflammatory biomarkers to avoid corticosteroid overuse and ineffective treatment but also exert unique disease-modifying effects. These agents can reshape immune homeostasis, block the progression of atopic diseases, and prevent the comorbidity of multisystem allergic disorders. Accordingly, this review focuses on the pathogenesis of pediatric Th2-related allergic diseases, systematically analyzes upstream and downstream targeted biological agents against Th2 inflammation and their application in stratified precision diagnosis and treatment for children, and clarifies the distinctive disease-modifying advantages of novel biological agents relative to conventional therapies. This review also discusses future directions for individualized targeted intervention, aiming to provide new insights for the standardized whole-cycle clinical management of pediatric allergic diseases.