The regulation time is an important index for formation switching control of connected and automated vehicle (CA V) platoon. This paper proposes a time-aware formation control (T AFC) strategy to improve the formation switching performance of CA V platoon. To construct an effective information sharing mechanism among the vehicles in the platoon, a unidirectional weighted graph is designed to construct the relation of the CA V platoon and calculate the impact factor between two different vehicles. Based on the unidirectional weighted graph, the time-aware requirement is converted to the regulation order problem, and the regulation order which corresponding to the minimum time is designed. According to the T AFC, the qualitative regulation strategy of the CA V platoon and the quantitative tune-up strategy of the vehicles are determined. In order to analyze the performance of the TAFC strategy, two state-of-art methods are selected as the benchmarked methods. The validation results demonstrate the proposed method possesses better performance for formation switching control compared with the benchmarked methods.