In recent years, the aging of the population and the tightening of the labor market have made the relaxation of the two-child policy a pivotal measure to promote population growth. As an essential part of socio-economic development, urban families’ changes in the cost of their children’s education investment under the two-child policy are significant in understanding the policy effect and optimizing the demographic structure. This paper analyzes the impact of the two-child welfare policy on urban families’ education investment costs using the HOV model to provide data support and decision-making reference for policy formulation. The research methods include analyzing the distribution of educational resources, predicting the impact of the two-child policy on the cost of educational investment using the HOV model. The cost of educational investment for urban families increased significantly after the two-child policy was implemented. The average price of educational investment increased by 15%, and the impact was more noticeable for low-income families. The two-child policy is beneficial for population growth but also increases urban families’ educational burden. It is recommended that the Government optimize the relevant welfare policies to reduce the burden on families, and at the same time improve the allocation efficiency of educational resources to ensure the sustainability and fairness of the policy.