More wind and solar power will be integrated into future power systems in China. Assessing the complementarity of wind and solar resources helps to mitigate the fluctuation of renewable power output effectively. This study comprehensively assesses the complementarity of wind and solar resources over China based on MERRA-2 reanalysis dataset. The results show that the complementarity between two resources and that between different regions for a single resource are significantly affected by the time scales. The complementarity between wind and PV power plants is superior to that between wind or solar power plants in different regions. Furthermore, the complementarity between wind and PV power can be further improved by dispersing the locations of wind farms, especially when the PV power is significantly positively correlated with wind power at the same location. However, dispersing the locations of PV plants may not work since the diurnal and seasonal solar radiation are highly similar in different regions. Extreme value analysis is employed to assess the benefits obtained from the wind-solar complementarity. The duration of no power output and the hourly negative fluctuation in power output are significantly reduced due to the complementarity. (C) 2019 Elsevier Ltd. All rights reserved.