This paper reviews the wind turbine aerodynamic noise and mechanical noise mechanism and the de noising methods in healthy condition monitoring (HCM). Fast development of the wind farm brings the problem of noise pollution, which can influence both the environment and the safety running of the turbine. To maintain the healthy running of the wind turbine, vibration-based signal analysis methods are introduced into wind turbine research. However, the noise interruption makes the feature extraction difficult in HCM. In order to suppress the noise, aerodynamic noise mechanism and mechanical noise mechanism are first analyzed separately. More and more wind turbine de-noising methods are proposed in recent years. Aerodynamic noise can be suppressed by structure optimization of the blade or the whole coupling system, or other similar numerical simulation and optimal methods. Mechanical noise can be de-noised by effective signal processing methods. Some ideal technologies are still needed according to the special characteristics of the wind turbine. (C) 2017 Elsevier Ltd. All rights reserved.