Taking Shandong Peninsula urban agglomerations as the research area, and the accessibility indicators and the gravitation model were used to analyze the impacts of high-speed rails on the accessibility and economic linkage in the research area. The results show: ① After the opening of the high-speed rails, the weighted mean travel time of each city along the rail is significantly reduced, which presents distinct core-edge characteristics, and the space-time convergence effects have been caused; the daily accessibility of cities along the high-speed rail has been greatly improved, whose rate of change shows strong hierarchical feature and has obvious layers, and the accessibility pattern shows significant "corridor effect". The construction of the high-speed rail has also promoted the improvement of the spatial equality of the peninsula urban agglomeration, and the accessibility of global transportation tends to be fairly distributed. ② The high-speed rails reshape the economic linkage spatial pattern of Shandong Peninsula urban agglomerations, making it along the axis of the high-speed rail with Jinan and Yantai as the core. The opening and construction of the high-speed rails also produce the regional difference of economic linkage aggregate, Jinan’s external economic linkage intensity is the strongest among all the cities. Affected by the layout of the high-speed rails, the spatial pattern of economic linkage aggregate takes on a “dual-core” model centering on Jinan and Weifang, which has been showing an increasing centrality. Finally, this paper gives the further discussion of promoting the healthy development of regional economic in Shandong Peninsula urban agglomerations based on the high-speed rail construction.