The appearance and development of highway affected Urban Agglomeration Spatial Interaction deeply. The research about it can help to grasp the development evolution and the mechanism of the spatial structure of urban agglomeration. Took Shandong peninsula urban agglomerations for example; make use of gravity model, the boundary model, capture effect of space of highway model and urban agglomeration spatial compactness model to calculate and analysis. The results showed that the changes of space gravity inside urban agglomeration were closely connected with the density of highway; the operation and construction of highway impacted on the competition for space between cities, different capture effects turned up at same time; urban agglomeration spatial compactness was also raised. Besides, capture effect of space of highway was proposed, in order to qualitative analysis the effect of which the highway impacted on the compaction for space between cities in a certain period of time.