Abstract: Distributed Coherent Aperture Radar (DCAR) combines transmitting and receiving coherent synthesis to effectively form a higher gain virtual radar from dispersed multi unit radars, combining unique advantages such as information augmentation and resistance to damage. Due to the sparse array nature of DCAR, its spatial beam shape differs significantly from phased array radar and is closely related to spatial position, making it difficult to describe based on angles. Additionally, solving point by point in space requires significant computational resources. In response to this issue, this article uses the spatial grid as a tool to analyze the relationship between DCAR synthesis energy and spatiotemporal coordinates, design grid partitioning rules, and exchange space for time to efficiently characterize the spatial beam shape of DCAR, which can effectively support the practical application of DCAR. The simulation experiment verified the effectiveness of the proposed characterization method.