Abstract: The data collected with in6 hours after significant earthquakes of 103 earthquake sequences （since 1966） have been analyzed systematically,the results show number of earthquake sequence in eastern region is obviously lower than that in western region of China,fewer for Heilongjiang province and its neighbor region.The time distribution function of earthquake frequency is mainly power function and exponential function.Exponential distribution is more for sequences of double earthquakes or cluster. Power function is more for main shock-aftershock sequences.There is not linear correlation among h、k values,number of earthquakes and time gap of main shock-aftershock.The time distribution function and h value is related with time gap between fore-shock and remarkable earthquakes,and the time distribution function is mainly exponential distribution,h value is less than 0.5.

Key words: Earthquake sequence, Remarkable earthquake, Time gap, h value, k value