A wind turbine condition monitoring method was proposed based on SCADA data co-integration analysis. The co-integration residual obtained by the co-integration process of the SCADA data of the wind turbine was used for monitoring the operation state of the wind turbine. Taking the experimental data of a 1.5 MW doubly-fed wind generator under different environments and operating conditions from Jinjie Company in Baotou City, Inner Mongolia, the effectiveness of the proposed method was verified. A two-stage co-integration process was performed on multiple process parameters of the wind turbine, and the data trend had non-linear characteristics. The method was tested with known failure cases. The results show that this method can effectively monitor the running status of wind turbines.