The increasing prevalence of child and adolescent overweight and obesity (CAOAO) in Beijing poses significant health and economic challenges. This study assesses the potential health and economic outcomes of implementing specific interventions to address CAOAO in Beijing. A deterministic Markov cohort model was used to estimate the impact of five interventions from 2025 to 2115: restrictions on unhealthy food marketing to children, mandatory front of package labeling (FOPL), family-based nutrition and exercise education, school-based nutritional health education, and nutritional counseling in primary healthcare. The model evaluated societal costs, healthcare savings, wages, and economic productivity in adulthood, calculating the return on investment (ROI) for each intervention and their combined effect. Without intervention, Beijing is projected to experience a loss of 13.4 million disability-adjusted life years (DALYs) due to CAOAO. The health and economic impact of childhood obesity in Beijing is projected to be CNY 14.6 trillion (USD 2.1 trillion), or a lifetime loss of CNY 6.8 million (USD 0.96 million) per affected child, exceeding the sum of Beijing's GDP from 2021 to 2023. Restrictions on unhealthy food marketing to children and nutrition counseling in primary healthcare are projected to yield the highest returns, with benefits accruing within one year of implementation. Owing to the substantial upfront costs, including personnel, materials, and training, school-based and family-based interventions require a longer time horizon to realize significant health and economic benefits. Effective management of CAOAO in Beijing demands a multifaceted approach. The combination of restrictions on unhealthy food marketing to children, mandatory front of package labeling, nutrition counseling in primary healthcare, school-based intervention, and family-based intervention presents the most substantial health and economic returns. This comprehensive strategy aligns with global best practices and addresses the unique challenges faced by Beijing in combating childhood obesity.