Abstract: Based on the panel data of 30 provincial-level regions in China from 2014 to 2023, this paper adopts the location quotient to measure the agglomeration degree of producer services, and uses the entropy weight method to calculate the comprehensive indices of digitalization development and high-quality economic development. A Spatial Durbin Model is constructed to test the spatial spillover effect of producer services agglomeration on high-quality economic development, and a threshold model is further applied to identify the threshold characteristics of digitalization development in the above correlation. The empirical results are as follows: (1) There exists prominent regional differentiation in digitalization level, producer services agglomeration degree and high-quality economic development level; (2) Producer services agglomeration exerts a significantly positive spatial spillover effect on high-quality economic development in both local and neighboring regions; (3) Digitalization development is subject to a single threshold constraint, and its marginal driving effect decreases gradually with the improvement of digitalization level.