High-quality economic development (HQED) has recently become a prominent issue in China. The HQED of the Yangtze River Delta (YRD) has played an exemplary role in achieving the leap from "China speed" to "China Quality." However, the quality of economic growth (QEG) has various specific manifestations, such as inclusive green growth (IGG), and green transformation development (GTD). Based on the panel data in the western YRD of China, we first explore how to measure the scientific and technological innovation (STI) index and IGG index using the improved multidimensional comprehensive evaluation method (IMCEM). Then we conduct a comparative study to examine the impacts of STI on the quantity and quality of economic growth both on the mean effects and conditional distributions. Finally, we explore the impact of STI on GTD, the heterogeneity, and the mediation and moderation effects. The results show that (1) The EMCM is effective in the calculation of the STI index and QEG index. (2) STI has a promoting effect on two kinds of economic growth under mean estimations and quantile distributions. Further, the promoting effect of the quantity of economic growth is higher than the quality. (3) STI effectively promotes the regional GTD, and with the increase of the GTD index, the driving role of STI also grows. (4) STI has a heterogeneous impact on GTD at different dimensions of innovation, periods, and regions. (5) The mediation effect indicates that promoting the emerging industries agglomeration (EIA) is an essential mechanism for STI to release the dividends of GTD. The moderation effect of reform and opening up (OPEN) merely on the direct effect is significantly positive.