Transmission line tripping accidents caused by wildfire disasters are one of the main reasons that jeopardize the safe and stable operation of power grids. For this reason, based on the analysis of fire spot data in a region over the years, a wildfire risk assessment method based on expert experience and data fusion is proposed. Firstly, survey records of fire spots near transmission lines are collected, and localized fire disaster data are screened to construct a dataset; then, the dataset is expanded based on expert experience; finally, the constructed dataset is utilized to train a logistic regression model; and obtain the optimal parameters of the model. The results show that the accuracy, precision, recall, and F1-score of the method proposed in this paper for predicting the development of a fire point into a localized fire are 0.93, 0.89, 0.89, and 0.89, respectively, and the risk of wildfire can be effectively assessed. The results of the study can provide a reference for the prevention of wildfire disasters in transmission line corridors.