Offshore wind energy is a promising solution to the environment and energy crisis thanks to its excellent performance of production.It would be further developed with the support from low-carbon economy.This paper summarizes the configuration of offshore wind power systems and surveys their optimal planning methods.Methods of offshore wind farm siting，common topologies of collecting systems and different transmission schemes are reviewed，while reliability evaluation is discussed in detail.Based on this，modeling approaches and algorithms for optimal planning of offshore wind power systems are briefly treated.Finally，some suggestions for potential research directions of optimal planning of offshore wind power systems are made.