The amplitude data of UHF-band ionospheric scintillations were recorded at a low-latitude station of China, Haikou station (geographic: 20.00oN,110.33oE), during the high sunspot activity year of 2013. Based on these data, the Welch algorithm of the Fast Fourier Transform methods was used to analyze the scintillation intensity power spectra, and four types of typical intensity power spectra were found and presented. A nearly sinusoidal fluctuation in the east-west horizontal direction was found in the irregularity structure by analyzing the contour map of spectral density as a function of local time and spatial scale. The spectral index p of the ionospheric amplitude scintillations was extracted for the year of 2013, and the variation of the spectral index p was analyzed by statistical method and an empirical model of the spectral index p over Haikou station was put forward, which was applied in the empirical Climatological Model of Scintillation Occurrence Probability (CMSOP) over the low-latitude of China. Finally the prediction of ionospheric scintillation occurrence over Haikou station from CMSOP is compared with the observations.