Abstract: Based on the Global Telecommunication System(GTS) data from 2014 to 2016, a statistical analysis from eight radiosonde stations data near South China Sea(SCS)is given in this paper. We obtained the annual duct parameters and probability distribution characteristics of the lower atmospheric ducts. Annual statistics show that the probability of surface duct occurrence in the South China Sea is about 20%, and most surface duct heights are below 100 m and the duct intensity is smaller than 10 M. The probability of elevated duct occurrence is about 50%. The parameters of top height, bottom height and bottom height of elevated duct are generally between 1 000 and 2 500 m, and the intensity is 4 M-15 M. The spatial distribution of atmospheric duct is high in the middle part and low in the north and south part, which is related to the inter tropical convergence zone(ITCZ). Monthly statistics show that there are obvious monthly variations in the northern and central South China Sea, which closely relates to the South China Sea monsoon, while the variations are not obvious in the southern South China Sea area (the area near the equator). These statistical analysis results can serve as a reference for radar and communication system working or operating in this sea area.