10.18170/DVN/I9JJIY Donghe Zhang0000-0002-3880-2426(Peking University) Peking University Open Research Data Platform 2021 Here two files include the ionospheric foF2 and hmF2 data observed at China Haikou ionosonde station (20.02°N, 110.2°E, MLAT~ 9.32°N) in 2003 (16 April to 31 May) and in 2004 (21 Sep to 26 Oct ), respectively. The first column is the Day of year (DOY), the second column is the foF2(Mhz), the third column is the hmF2(km). Yongqiang Hao(Peking University)