Abstract: The earlier prosperous regions boosted the latter regions, which is an important way to promote balanced development among regions and to achieve common prosperity. The article uses the data of the provincial panel from 2010 to 2020 and the spatial model, trying to discuss whether the earlier prosperous regions boosted the latter regions by the spatial spillover effect. According to the inter-provincial common prosperity index, the earlier prosperous regions and latter regions are divided, and the earlier prosperous regions drives the development of the latter regions through the spatial spillover effect. The mechanism analysis shows that the spatial spillover effect of the earlier prosperous regions to the latter rich areas is mainly manifested in four dimensions: high-quality economic development, spiritual-cultural prosperity, equal public service and ecological civilization construction. Further research shows that the spatial spillover effect of provincial counterpart assistance is statistically significant, and the driving effect is mainly manifested in two dimensions: high-quality economic development and spiritual-cultural prosperity. The spatial spillover effect between the earlier prosperous regions and the latter regions is affected by the geographical distance, and the driving effect increases first and then decreases with the limit of 1, 400 km. In particular, when the geographical distance exceeds 1, 400 km, the spatial spillover effect does not show statistical significance.