Electromagnetic leakage detection is very important in the area of network attack and defense system. Electromagnetic leakage detection can be divided into initiative detection and passive detection. The initiative detection mainly adopts the way to launch signal to special equipment and then detect current/voltage in specific location. When we get this useful information, we can get the knowledge of leakage information or other feature information of specific equipment. This article tries to build an equivalent model based on a kind of initiative conduct electromagnetic leakage source. According to the working frequencies, it builds two models: the equivalent antenna model and the equivalent circuit model. To verify the accuracy of these two models, the article provides theoretical analysis and simulation verification accordingly. The research of these equivalent models are beneficial for further study of electromagnetic leakage detection.