This paper investigates the connotation of new quality productivity, integrating existing research findings to construct a measurement index system tailored for our country, and conducts an in-depth analysis of its impact on economic growth. The study utilizes provincial panel data from Chinese provinces spanning 2012 to 2022. The results indicate that, in contrast to prior studies, new quality productivity influences economic growth not only through supply-side mechanisms but also plays a pivotal role in demand-side transmission; notably, the upgrading of consumption structures and the expansion of investment domains exert both direct and indirect effects. Accordingly, this paper proposes relevant policy recommendations. The innovative aspects of this study are as follows: 1. Measuring new quality productivity across multiple dimensions by incorporating environmental and ecological factors while exploring its transmission mechanism from the demand side; 2. Introducing dynamic quantitative analysis to simulate the operational mechanisms of new quality productivity on consumption and investment; 3. Empirical tests demonstrate that after addressing issues related to heterogeneity, endogeneity, and robustness, the transmission mechanism of new quality productivity remains significant and robust.