China is one of the countries which have the most earthquake disasters in the world.A total of 23 M≥8 earthquakes occurred in Mainland China from 1303 to 2011.The seismic activity of M≥8 earthquakes has showed an obvious self-organized orderliness.The main ordered values are 252-258 a,108-112 a,94-98 a,44-47 a,24-25 a,16-19 a and 11-14 a.According to the information forecasting theory of WENG Wenbo and combining ordered analysis with complex network technology,we build the informational ordered network structure of M≥8 great earthquakes in Mainland China,and summarize the prediction research on two great earthquakes (the 2001 Kunlunshan M8.1 and the 2008 Wenchuan M8.0 earthquake) during the beginning of the 21^st century in western Mainland China.At last,we present new prediction opinion that the future M≥8 great earthquakes will probably occur in 2022,2026,2045 and 2065 pre and post in Mainland China.The results show that an M≥8 great earthquake can be predicted and the network feature is the formation mechanism of great earthquakes.Ordered network method produces satisfactory results in moderate and long term prediction for M≥8 great earthquakes.