This paper provides a statistical study of the disturbance of ionospheric electron content initiated by solar flares over importance one for 1978-1979. It shows the different effects of solar flares grouped by their importance, duration, season and the distance from the solar central meridian. The results show that ionospheric electron content is obviously disturbed by the bright solar flares with duration longer than 1.5 hours. The electron content starts to increase after the occurrence of solar flares and reached its maximum on the fourth-fifth day. The electron content disturbances caused by non-bright flares is smaller than by bright filares. Solar flares with duration <1.5 hours do not disturb the electron content. The flares occurred in the summer seems not to disturb the electron content. Only the flares occurred in the winter obviously disturb the electron content. There is an east-west asymmetry in distribution of flare’s position in causing the electron conten distinct disturbances. Flares occurred on the east 61-90E from the solar central meridian and in winter seasons induce the largest disturbances for the electron content.