Abstract: Distributed generation access to distribution network is one of the key issues to realize the smart grid. The data transmission of communications is strictly constraint because of the time characteristics of the protection and control functions. In this paper, the delay requirement of protection, control and measuring is firstly analyzed according to IEC 61850 and IEEE 1547 standards. Then wired and wireless communication technologies that may be used in distribution network are studied according to practical distribution network. Finally, taken a typical DAS as an example, the simulation models of wired communication based on twisted pair cable Ethernet and optical fiber Ethernet are built, and the simulation models of IEEE 802.11 is also set up based on spread spectrum technology. The simulation results show that all the proposed communication technologies satisfy the delay requirement of protection and control in the distributed network with distributed generation.