This paper presents a kind of visualization model for electromagnetic signals according to battle actualities and tactics needs. In modern battles, complex electromagnetic environment is difficult to control as its invisibility and variety. According with the requirement of tactics application, the proposed model provides a new way to simulate electromagnetic environment for acquiring information dominance. The key techniques are introduced in detail, such as electromagnetic signal modeling, electromagnetic situation evolution and combat scheme simulation. The general framework of the visualization system are designed and realized for naval combat application. The implementation of the techniques and the system greatly enhance naval officers' commanding ability in electromagnetic campaigns.