Abstract: In the report， the ground and high-altitude observation data of national sites in Hainan Island for ten years were used to study the applicability of CRA reanalysis data in Hainan Island. The results showed that CRA has good applicability in Hainan Island. For the ground elements， the applicability of the 2 m air temperature of CRA in Hainan Island is the best， the 2 m relative humidity is the second， and the 10 m wind speed is relatively general. 2 m air temperature and the relative humidity present obvious seasonal changes， the site differences under 10 m wind speed were more significant. The CRA high-altitude data have obvious differences at different heights and sites. The applicability of the middle troposphere is better than that of the lower and upper troposphere， and it is better at Sanya site and Yongxing site than that in Haikou