How to monitor and predict icing load of power transmission lines are important problems for the reliability of power grid. A model based on data-driven is presented here to predict the icing load of transmission line, which is available to forecast the icing disaster of it. The fitfulness, which influencing the prediction results of icing load, is analyzed and discussed in this paper. According to the results of simulation, this model has a good accuracy of prediction if the training data and prediction data are in the same icing process. If the icing process is not same but contiguous, it also can predict the degree of icing load qualitatively.