The "Hu Line" is a geographical line connecting Heihe City and Tengchong City in China. It is densely populated on the southeast side of the "Hu Line" but sparsely populated on the northwest side. Since the implementation of New-type Urbanization strategy in 2014, the spatial pattern of population distribution on both sides of the "Hu Line" has changed a lot. We put forward the "Quasi-Hu Line" based on the boundaries of prefecture-level administrative divisions. According to the seventh population census data in 2020, this study focuses on the new characteristics of population spatial patterns and population growth patterns on both sides of the "Quasi Hu Line" from 2010 to 2020. We analyze the driving factors combined with the development of New-type Urbanization. The main conclusions are as follows: (1) The human-land relationship reflected by the "Hu Line" was still stable, and the overall distributions of densely populated and sparsely populated areas were also steady. In 2020, the population ratio of the southeast side to the northwest side was 93.5∶6.5. (2) The population share of the northwest side still increased slightly, but the increment was significantly lower than that before 2010. (3) The centralization index of the population on the northwest side turned from decline to increase after 2010, which indicated the concentration of spatial population distribution in the northwest half was similar to that in the southeast half. (4) The spatial differentiation of population growth on the southeast side has been strengthened. The negative population growth area accounted for 54.22% of the southeast side from 2010 to 2020, exceeding the positive population growth area. The population growth on the northwest side had also changed from the "relative balance" model to the "Matthew effect" model, with the negative population growth area accounting for 26.14% of the northwest side. (5) The relative population growth advantage of provincial capitals was becoming much more prominent. The spatial polarization process of population growth slowing down or negative growth was formed in the surrounding areas of provincial capitals. In addition, such a process on the northwest side was more significant than on the southeast side. (6) The driving factors, including the level of economic development, the scale of urban population size, and the level of administrative divisions, significantly impacted population growth. For the northwest side, the level of administrative divisions had a particularly significant impact on population growth, while the impact of urban agglomerations was not noticeable. In general, the northwest side had begun to present similar population spatial distribution patterns and driving factors with the southeast side. In the context of population migration and urbanization, the novel patterns of spatial population distribution reflected a kind of "breakthrough" of the "Hu Line". With China's total population turning to decline and urbanization entering the mid-late stages, more attention should be paid to the regional differences and coordination of demographical structures on both sides of the "Hu Line".

Keywords： the "Hu Line"; spatial population distribution; population growth; the New-type Urbanization; the seventh census; China