In order to adapt to the intelligent, efficient, economic operation of DC grid, to realize cooperation of different distributed power supply and load, based on demand of six terminal tree DC grid physical simulation platform, a system level coordinated control strategy suitable for renewable connected grid is proposed. The six terminal grid is regarded as a multi input multi output system, bond graph method is utilized to extract state space equation of the grid, after analyzing the dynamic characteristics of the system, the optimal target of closed-loop poles placement is determined, and linear system integration method is proposed to design the state feedback controller. Finally, the model in Matlab/Simulink platform is built, compared with traditional master-slave margin controller, simulation result of the proposed state feedback controller has obvious inhibitory effect on voltage fluctuation brought by renewable energy. This work is supported by National Basic Research Program of China (973 Program) (No. 2012CB215204).