Gurney flap and trailing-edge wedge are useful devices to improve the aerodynamic performance of aerofoils for wind turbines; however, the researches on blunt trailing-edge aerofoil are limited. In this paper, we focus on the flow mechanism of Gurney flaps and trailing-edge wedges and their impacts on a blunt trailing-edge aerofoil DU97-W-300. Two-dimensional Computational Fluid Dynamics (CFD) models were built with Reynolds-averaged Navier-Stokes framework, and the models were further validated with experimental results. Moreover, the main aerodynamic parameters including lift coefficient, drag coefficient and lift to drag coefficient, are calculated to evaluate the aerodynamic effects of these two devices. And flow fields around the aerofoil and these two accessories are presented and further analysed in detail. The numerical results show that Gurney flap and trailing-edge wedge improve the maximum lift coefficients of aerofoil DU97-W-300 by 23% and 30% respectively. Compared to Gurney flap, trailing-edge wedge presents better performance because of the larger structure strength and lift improvement.