Abstract: Based on researches of unsteady state of earthquakes in China continent, this research divided the status of activity of M>7 earthquakes in China continent into three types, they are intermittent (quiet) phase, sporadically occurring phase, frequently occurring (active) phase, respectively. Then this research analyzed the different types by means of the significance test and concluded that the basic status of earthquake activity in China continent may be sporadically occurring phase; the intermittent or frequently occurring status may deviate from the sporadically occurring status. As for earthquake activity of China continent during the last century, there is no obvious difference of the earthquake activity during the former fifty years and the latter fifty years. The characteristics of future earthquake activity may be as the same as the characteristics of earthquake activity during the last century. Based on the data since 1901, there always was a sporadically occurring phase before a frequently occurring phase. And there was not any case that earthquakes frequently occurred after intermittent phase. So Yutian 7.3 earthquake, on March 21, 2008, may be the symbol of the beginning of new sporadically occurring phase of earthquake activity in China continent.

Key words: China continent, Earthquake, Status of earthquake activity, Significance test