Communicable diseases such as flu and measles are transmitted through contacts. Given the context of modeling assumptions and disease mechanisms, various modeling frameworks have been developed. Among them, homogeneous mixing models such as the differential equation modeling approach have produced valuable results on epidemiology. However, most human interactions are not homogeneous. Network modeling is an appropriate approach utilizing contact pattern information and give a higher resolution of epidemic dynamics. In this chapter, we introduced homogeneous mixing model and the concept of networks. After the introduction, the connection of network to epidemic dynamics is covered with an example of non-homogeneous mixing with the syringe sharing model of IDU population on Hepatitis C.