Abstract: In this study, the characteristics and applicability of wind resources in offshore China are analyzed using the reanalysis data of ERA5 (European Centre for Medium-Range Weather Forecasts Reanalysis version 5), CFSR (Climate Forecast System Reanalysis), and MERRA2 (Modern-Era Retrospective analysis for Research and Applications version 2) and the observation data of 13 ocean stations and three wind towers in offshore China. Results showed that the weak wind frequency of reanalysis data in the East China Sea and South China Sea is higher than that in the Bohai Sea and Yellow Sea. The cumulative probabilities of weak wind (＜6 m/s) of ERA5 in all sea areas are 38.99% (44.95%), 43.63% (47.54%), 60.74% (41.63%), and 47.94% (38.19%), higher than that of CFSR (MERRA2). In all three reanalyses, the distributions of effective wind time (EW) in offshore China are similar (84%–95%). The value of mean wind energy density (WPD) showed the “low–high–low” spatial distribution from north to south; the Taiwan Strait had a high WPD value (＞4000 W/m²). Regarding the stability of wind energy, the daily variation of ERA5 and CFSR is weak in the south and strong in the north, while the daily coefficient of variation (CV) of MERRA2 is between 1.03 and 4. The performance of ERA5 is better than that of CFSR and MERRA2. The MERRA2 reproduces the daily fluctuation of wind energy in the Bohai Sea and the South China Sea. Moreover, CFSR has certain advantages with respect to the EW and WPD of the Yellow Sea and the CV of the East China Sea and the Yellow Sea. According to the above-mentioned conclusions, the applicability of reanalysis data to different indicators of offshore China wind resources varies. Consequently, based on the requirements and data conditions, using different types of reanalysis data for different sea areas in wind resource assessment research and work.