Abstract: The main characteristics and mechanism of Wenchuan earthquake and its aftershocks were briefly introduced; the problems of earthquake prediction are discussed. The author considered that the intermediate and long term predictions are believable, according to the data of history earthquakes, and it is difficult to make sure the short term prediction. Based on the earthquake periodicity of China continent during last hundred years, the distribution of strong earthquakes is discussed during tens years later. Depending on the history earthquake data in last thousand years, the author discuss the strong earthquake, such as Tangshan earthquake in 1976, will occur at North China area after 240 years and before 300 years.

Key words: earthquake, mechanism, earthquake periodicity, history earthquake