Abstract: In order to better grasp the fading characteristics of radio signals in tropical ocean regions, we collected the data of electromagnetic signal characteristics at 25 positions in the South China Sea. This data is covering the frequency of 99 MHz, 160 MHz, 600 MHz, 830 MHz and 1 000 MHz. The fading distributions of the channel in above region are evaluating through Kolmogorov-Smirnov statistical method. And the mathematical model of normalized amplitude envelope is established by least squares method. The analyzed results show that: 1) there are mainly Gauss and Rice distributions in this research region; 2) the polarization type and signal frequency have little impact on the fading distribution types; 3) the mean of normalized amplitude in the above five frequencies are 0.531 1, 0.545 2, 0.523 8, 0.546 1, 0.534 7 respectively, and the standard deviation of that is 0.265 1, 0.275 4, 0.280 9, 0.275 5, 0.276 6 respectively. The above research results provide technical support for localization modeling of wireless channels in the South China Sea.