This paper deals with the relationship between great earthquakes and cosmic environment. The statistical results show that the great earthquakes(M≥8)in Chinese continent and its adjacent regions relate evidently to the revolution of the earth and mostly occur at the intervals when the earth rotation speed gets faster; the events in Chinese mainland have some correlations with sunspot activity, conjunction of the nine planets and return of Halley's Comet; ones in West China and its adjacent regions display significant 18.6 yr. periodicity. These correlations suggest that the development and occurrence of great earthquakes are probably influenced by the cosmological environment conditions.