Under the background of continuously strengthening of inter-regional factor mobility, the effect of factor endowment on regional economic growth is inclined to weaken, and the scale effect and innovation externality are increasingly becoming important factors to promote China’s regional economic growth and inter-regional growth transmission. Our analysis attempts to introduce the scale effects and innovation externality into the analysis framework affecting regional economic growth and use the provincial panel data to conduct empirical test on it. The empirical studies show that regional market scale and innovation externality have significantly positively boosting effect on regional economic growth, and that industrial scale has positive influence on regional economic growth but the influence is not obvious. China should set up and perfect city-cluster-centered space governance system, intensify inter-regional innovation spillover effect, and raise regional space linkage network extent to boost regional economic growth quality and regional economic coordinated development.