Turbulence is an important disturbance source of environmental airflow during aircraft flight. Turbulence easily leads to problems in many aspects such as aircraft structure and performance, so turbulence seriously threatens flight safety and mission execution. Due to the characteristics of the large lift-acting surface of the flying-wing airplane, the influence of turbulence is especially obvious. In this paper, a model-assisted extended state observer (ESO) is designed based on the prior information from dynamics of the aircraft, and the turbulence disturbance is observed based on the idea of frequency division. The turbulence suppression compensation controller based on ADRC structure is designed to realize the turbulence suppression. A flying-wing UAV is taken as the research object, without changing the current control architecture, the proposed algorithm is incorporated to carry out verification. The numerical simulation shows that the turbulence observation and suppression algorithm can effectively reduce the influence of turbulence on longitudinal angular rate of aircraft of UAV.