Abstract: Solar activities may influence atmospheric electric properties, Atmospheric electric properties may play a critical role in the formation of thunderstorm. The effects of solar activities on atmospheric electricity may at last .influence the formation of 'thunderstorm. The analysis of the relationship between IMF section boundary crossing, solar flare, sun spot eleven year cycle variation and thunderstorm index is given using superposition epoch merthod for more than 13000 thunderstorm data from 10 metero-logy stations in Beijing area and Northeast region during 1957 to 1978. The results show that for some year's there exists correlationship between thunderstorm index and positive IMF sectiofn boundary crossing. The thunderstom index increases obviously within three days near crossing and on the seventh day after the crossing. The influence of the crossing on thunderstorm is stronger in the former half year than the latter half year. For different classes of solar flares, the influenced are not equally obvious The solar flares appeared on the weat side, especially in westen region, one (from0° to 30°) have most obvious influence. There is no discernible correlationship between thunderstorm index and sun spot eleven year cycle.