Based on the project division of power transmission and transformation projects, this paper analyzes a large number of practical engineering cases, and summarizes the influencing factors of substation and overhead line project cost combined with the practical engineering experience of many experts, A number of cost control indicators are extracted, and a combination prediction model of project cost based on neural network and support vector machine is constructed. The actual project data are taken as samples for empirical research. The results show that the combination prediction model is feasible and accurate for the prediction of power transmission and transformation project cost, which provides a new idea and implementation method for the prediction of power transmission and transformation project cost.