This paper proposes the planning and navigation of a surgical robot to perform safe and effective operations using finite element analysis results based on physical models of the brain. The physical brain models were determined based on the results of physical property tests. Finite element analyses of virtual tension tests were carried out under the same conditions as the actual tension tests, and the results of the analysis coincided with those of the test. The finite element analyses of robotic brain surgery were carried out using a two-dimensional structure, which consisted of the proposed physical models. Assuming two types of robot models are used (the brain spatula and capsule type robot respectively), stress distribution in the brain, caused by each robot model, was simulated in the analyses. The preoperative planning was considered based on the analysis results, and the safe velocity of the robot's movement was estimated as well. The results of this research showed that organ modeling was necessary for preoperative planning in order to implement safe surgery.