Abstract: In this paper, the turbulent inlet boundary is generated based on the CDRFG（Consistent Discretizing Random Flow Generation） method, and the unsteady characteristics of a pitch oscillating airfoil in turbulent flow is researched by using the large eddy simulation（LES）. The results show that the fluctuation characteristics of lift coefficient in downward pitch process is more obvious than that in the upward pitch process at the same angle of attack during the pitch oscillation of the airfoil. Compared with the uniform flow, the distribution of lift coefficient is relatively disordered with different amplitude abrupt characteristics in turbulent flow, and the fluctuation characteristics of lift coefficient is more significant, the longitudinal fluctuation range of hysteresis loop increases, and the unsteady characteristics of lift coefficient is aggravated in the pitch oscillation process of the airfoil. In addition, the fluctuation characteristics of lift coefficient caused by turbulence is more significant at small average angles of attack than those at large average angles of attack. The influence of turbulence on the surface pressure fluctuation is mainly located in the leading edge region of the airfoil, and the fluctuation pressure at the leading edge point has a strong response to the turbulent flow. Going back along the chord of the airfoil, the response of the fluctuation pressure on the airfoil surface to the turbulent flow weakens gradually.