Based on the bionics principle, this paper studies the influence of chord-wise flexibility on the energy extraction efficiency of the oscillating wing in turbulent environment. The energy acquisition performance of flexible oscillating hydrofoils with chord-wise deformation and rigid oscillating hydrofoils are numerically calculated by using computational fluid dynamics software Fluent. The power of hydrofoil with different flexibility coefficient and maximum offset at trailing edge under different conversion frequencies are compared. The differences between
the rigid wing and the flexible wing are analysed from the lift coefficient, momentum coefficient, energy extraction efficiency, streamline and hydrofoil surface pressure composite diagram. The results show that the flexible hydrofoil can change the direction of partial streamlines, increase the hydrofoil surface pressure difference and enhance the instantaneous lift force in a single period, thus improving the energy efficiency of the hydrofoil.