Abstract: As an important force in promoting agricultural modernization, industrial and commercial capital flowing to the countryside is also crucial for promoting common prosperity in rural areas and narrowing the wealth gap between urban and rural areas. This paper used data of Shandong Province from 2008 to 2022 to construct an indicator system from four dimensions: rural infrastructure, rural living environment, public service standarards and farmers' prosperity level. It employed the entropy method to measure the indicators of common prosperity in rural areas in Shandong Province, applied principal component analysis to evaluate the scale effect and promotion effect of industrial and commercial capital flowing to the countryside, and constructed a vector autoregressive model to analyze the impact of these two effects on common prosperity in rural areas. The research results indicated that, the overall level of common prosperity in rural areas of Shandong Province was on an upward trend. The introduction of industrial and commercial capital into rural areas initially led to a decline in common prosperity, but subsequently promoted an increase, ultimately enhancing the level of common prosperity in rural areas. Based on this, it was proposed to vigorously introduce industrial and commercial capital into rural construction and industrial development to enhance rural vitality, and to pay particular attention to promoting the diversification of rural industries in the process of introducing industrial and commercial capital.