The invention discloses a power transmission line fitting method and device. The fitting method comprises the following steps: obtaining an image of a power tower; extracting power tower head contourinformation from the image, and determining power tower head position information according to the power tower head contour information; obtaining a power transmission line detection area according tothe power tower head position information and filtering the power transmission line detection area; detecting the power transmission line detection area obtained after filtering processing to obtainpower transmission line position information; and carrying out power transmission line fitting according to the power tower head position information and the power transmission line position information to generate a power transmission line fitting result. According to arrangement characteristics of the power transmission line tower lines in the image, power tower head position information in theimage is extracted, and power transmission line position is detected, and power transmission line fitting is carried out; and the method has high accuracy, high robustness, few constraint conditions and has good adaptability to external complex environment.