Solid oxide fuel cells (SOFCs) are modular and flexible in relation to the fuel in use, and have the capability to be used for combined heat and power applications at high efficiency. Due to the advantages, SOFCs are emerging as an attractive energy generation option. As a generation resource, SOFCs could be used as a distributed one connected with a large power system and also could be planted in an islanding system. Research on the applications of SOFCs to power system is driven by the need to meet new energy targets, but is relatively immature compared to nuclear, wind, solar and other new energy technologies. Facing load changing performance of the SOFCs which inter-connected with a large system is simulated by Matlab. An islanding system with SOFCs and other distributed generation resources (DGRS) embedded in is also analyzed. This paper concludes with some suggestions of future applications of SOFCs for power generations.