Abstract: The ionospheric electron content (IEC) has been measured at Beijing for almost a whole solar cycle since 1980. From the analysis of the data, the following conclusions are obtained: there are undisturbed diurnal double-peak variations, noctural peak and a specific two-peak curves showing a subpeak before noon and a main peak after noon, although the variations of diurnal, seasonal and annual IECare recorded in high probability. It is the purpose of this paper to give the double-peak characteristics and nocturnal peak at Beijing and their variation in solar cycle. The results is compared with those of other scientists.