Aiming at the solution of urban ring road traffic signal control problem, this paper proposes a green wave coordination method for loop intersections based on multi-agent system's autonomy, distribution, coordination and active learning. Every intersections is regarded as an intelligent body and the adjacent agents can communicate and exchange information. Using the intelligent system memory storage and reasoning learning ability, the green wave coordination optimization of multiple intersections is performed on the loop. The algorithm is described and deduced from the perspective of algorithm model, parameter description and phase selection strategy under coordinated mode. The effectiveness of the proposed algorithm is verified by experimental simulation.