Abstract: In this paper, it is considered that the occurrence of strong events M≥6 in Tangshan within a radius of 85 kilometres in coming 200 years has a certain immunity basing on the analysis of recurrence penod of strong earthquakes in North China and the characteristics of the tempalspatial distribution ofevents with M≥6 after each strong event M≥7. According to the attenuation feature of the Tangshanearthquake sequence, it is considered that the maximum magnitude of strong aftershocks is about 5 inthis region in several decades of years in the future. The probability of occurrence of events with M≥6 will be very small.