Population regulation has long been a major policy arrangement faced by megacities in population development. However, there are many perplexities in academia about whether and what the population in Beijing needs to be regulated by the government and how to regulate it in the future. Based on the analysis of the population regulation periods in Beijing, the research focuses on the characteristics and challenges of the population regulation policy in the new period. The research concludes that Beijing's population regulation policy is characterized by its initiation into a major national development strategy, a shift away from relying mainly on administrative control, the coexistence of multiple regulation methods and the industrial decentralization beginning to play an important role, etc. Meanwhile, the population regulation in Beijing faces the challenges of how to accurately evaluate the changing situation of the population and how to ensure the vitality and sustainable development of the city while regulating its population. In the future, population regulation in Beijing is still necessary. In order to achieve the goal of sustainable development in Beijing, the research suggests that we should adhere to the goal-oriented and urban high-quality development, strengthen the top-level design of population regulation, increase indirect economic and market guidance, and strengthen the construction of talent team.