The declining birth rates, population ageing, and regional population differentiation urgently require China to optimize its population development strategy, high-quality population development becomes the main guideline. The guideline is derived from new development philosophy, driven by reform and innovation, centered around the high-quality life of the people, aimed at the comprehensive development of individuals and common prosperity of all people, serving the strategy of national rejuvenation. China has the economic advantages of wealth accumulation and high-quality economic development, talent advantages due to the comprehensive education system and the strategy for strengthening the country with talent, advantages in factor aggregation through new-type urbanization and urban agglomeration construction, the institutional advantage of the leadership of the CPC, and the cultural advantages of people-oriented and filial piety values. To make the most of these advantages, China should establish a comprehensive and integrated policy system for high-quality population development that covers fields such as science, education, culture and health, support for childbirth, labor employment, population ageing, and population security.

 This study examines the trends in and the impact of birth spacing policy on the second birth interval in China since 1970s using the population monitoring data in 121 Chinese counties．The birth spacing policy plays a significant role in regulating people’ s fertility behaviors thus slowing down population growth in China．Specifically，changes in second birth intervals have gone through three stages，a long-term stability before 1990s，an increase from 1990 to 2005 and a decline since 2006， implying a dynamic relationship with the birth interval regulation．Conditions for continuing the current birth spacing policy aiming at later birth，longer interval and less children no longer exist．Thus，the focus on birth spacing needs to be switched from a policy orientation to a health orientation．

This study examines the trends in and the impact of birth spacing policy on the second birth interval in China since 1970s using the population monitoring data in 121 Chinese counties．The birth spacing policy plays a significant role in regulating people’ s fertility behaviors thus slowing down population growth in China．Specifically，changes in second birth intervals have gone through three stages，a long-term stability before 1990s，an increase from 1990 to 2005 and a decline since 2006，implying a dynamic relationship with the birth interval regulation．Conditions for continuing the current birth spacing policy aiming at later birth，longer interval and less children no longer exist．Thus，the focus on birth spacing needs to be switched from a policy orientation to a health orientation．