Microwave ablation (MWA) is a clinically widespread minimally invasive treatment method for lung tumors. Preoperative planning plays a vital role in MWA therapy. However, previous planning methods are far from satisfactory in clinical practice because they only one-sidedly consider the surgical path or energy parameters of an MWA surgery. In this paper, we propose a novel planning model with a computational model of thermal damage to integrally optimize both the surgical path and energy parameters. To ensure the model can be solved in a reasonable time, we elaborate a search space reducing strategy based on clinical constraints. Simulation and ex vivo experimental results were compared with an average mean absolute error of 0.82 K and an average root mean square error of 1.01 K. Our planning model was evaluated on clinical data, and the experimental results demonstrate the effectiveness of our model.