中文摘要：

文章以中部省域为研究范围,将城市首位度作为经济增长的要素,利用阈值回归模型得到中部省域最优规模,其存在性同区域经济发展水平相一致,部分省域首位城市有其合理规模的上限。通过最优规模的实践性检验,超过最优规模依然可以对经济增长有增强性的推动作用,但增强的程度在逐渐减弱。研究表明,中部省域应积极构建合理的城市体系,通过调整首位城市规模,协同次中心城市,发展中小城市,以良好的城市结构实现经济快速、平稳的增长。

英文摘要：

This paper adopts provinces in Central China as the research object, and the urban primacy ratio as an economic growth factor,the threshold value regression model is employed to obtain the optimal scale for middle provinces in China. Their existence is in line with the regional economic development level. The primate cities in some provinces have an upper limit for the reasonable scale. The practices of the optimal scale suggest that the so-called optimal value refers to the measurement standard which contributes most to the economic growth. Even if the scale exceeds the optimal value, it can still boost the economic growth,but not so significantly. Research findings show that, in the middle provinces a reasonable urban system should be actively built to realize rapid, steady and sound economic growth through the adjustment of the primate city scale, the coordination between sub-center cities, medium-and small-sized developing cities, and the improvement of the urban structure.