Based on the daily maximum temperature from 18 national meteorological stations in the Hainan Island, NCEP/NCAR daily and monthly reanalysis data and NOAA SST data, the characteristics and cause of abnormally high temperature in the Hainan Island in spring 2019 were analyzed. The results are as follows: (1) The extremely high temperature days were more, maximum temperature was higher, and high temperature coverage in the Hainan Island was wider in spring 2019. (2) The west Pacific subtropical high (WPSH) was the dominant circulation system affecting high temperature in spring in the Hainan Island. The area of WPSH was larger, the intensity of WPSH was stronger and its position was to the west in spring 2019. Hainan Island was controlled by the stronger sinking motion of the WPSH main body. (3) In spring 2019, the westerly jet at middle and high latitudes over East Asia was stronger, the tropical convective activities over the south China Sea and the Philippines were inhibited, which were beneficial for strengthening, westward extending of WPSH and enhancing of local subsidence adiabatic warming. Meanwhile, combined with low-level warm advection transport, it was conducive to the local temperature rising, which further led to the development of high temperature. (4) From autumn 2018 to spring 2019, an El Niño event had formed in the tropical middle-east Pacific, and it was more prominent in autumn and winter. The tropical Indian Ocean was being warmer constantly, which was more prominent in spring. The distribution of SST anomaly was beneficial for strengthening and westward extending of WPSH, and then WPSH controlled the whole area of the Hainan Island in spring, forming extremely high temperature.