Due to the challenges of DC circuit breaker design and the coordination between DC terminals, the development of line commutated converter based multi-terminal DC system is very slow. The appearance of full control devices and new topologies for voltage source converter, especially the promotion and application of the modular multi-level converter, have brought opportunities and challenges for the multi-terminal DC system. This paper mainly discusses the bulk power transmission from energy base to different load centers. Different multi-terminal DC schemes for 3-terminal DC transmission system are analyzed and discussed. The advantages and disadvantages of these schemes are compared. Finally, the hybrid multi-terminal DC scheme based on line commutated converter and voltage sourced converter is proposed, which can solve the commutation failure problem in the inverter station, simplify the coordination between different DC terminal and has great economic significance.