Abstract: The problem of latitudinal dist ribution asymmetry for global great earthquakes (M≥ 7.0 ) has been discov ered earlier by the internatio nal geoscientific circle, but it is very dif ficult to explain. Statistics have been made in the paper for the lati tudinal dist ribution of g reat earthquakes (M≥ 7.0 ) occurred in the world in the last 100 years from 1900 to 1999. And it has been further proved that the problem of asymmetry in the di stribution of great earthquakes in the world does exist. The great earthquakes occurred in the northern and southern hemispheres are asymmet ric, there are more earthquakes in the no rthern hemi sphere and less in the southern hemisphere. The regions with concent rated earthquakes are asymmet ric in both hemispheres, it is 15°～ 55°in the northern hemisphere and 0°～ 35°in the southern hemisphere. There are three obvious regions with g reat earthquakes, they are 15°～ 20°, 35°～ 45°and 50°～ 55°in the northern hemisphere. There is not any great earthquake in the polar area. The authors have derived the fo rmulas to calculate the extreme values of solar and lunar latitudinal hori zontal tide generating forces to the crust. And the asymmet ric problem of global g reat earthquake dist ribution has been better explained based on the latitudinal dist ribution law when the solar and lunar tide g enerating forces reach the extreme values.

Key words: Distribution of global great earthquakes, Asymmetry, Dynamic explanation