Abstract：The main origin of the great Wenchuan Ms8.0 earthquake is a large GLE on January 20, 2005 which is the second largest GLE in recent 70 or more years since the continued observation of cosmic rays. Thus, in past 108 years at least 8 in all of 9 earthquakes of magnitude 8 occurred in China were caused by large enhancement of cosmic ray environment. The cause of formation of the Wenchuan earthquake reads as follows: Massive cosmic rays caused by large enhancement of cosmic ray environment produce current system in the ionosphere, through electromagnetic induction the current system produces inductive current system within the earth which produces burning gasifying cavity in the enriched region of uranium or thorium.The high temperature and high pressure further lead to nuclear fission combustion and nuclear fusion combustion in the burning cavity and then the very high temperature and very high pressure caused by continued nuclear combustion finally lead up to a burst of surrounding rock of the burning cavity , thus a large earthquake occurs. The observational data and seismic tomography have already confirmed that below the focus of the Wenchuan earthquake there is a very high temperature region. On these grounds,the paper proses a new idea and method for early warning large earthquakes.
