In this talk, the SIS epidemic model in hypernetworks is constructed. We also consider scenarios in which hyperedges that perform collective contagion and hyperedges that perform individual contagion coexist in hypernetworks. For SIS epidemic model in bi-uniform, its mean field model is investigated, and the stability of the disease-free equilibrium as well as the endemic equilibria is proved using the qualitative theory of differential equations, and the threshold value at which an epidemic can spread in a bi-uniform hypernetwork is obtained. The model is analyzed to give rise to a bistability phenomenon in which a disease-free equilibrium and an endemic equilibrium coexist. For SIS epidemic model in general hypernetworks, the constructed model is written as a hyperdegree-based mean field model, and the stability of the disease-free equilibrium as well as the existence of endemic equilibria are proved by using a specific hypernetwork as an example. We also obtain the threshold at which an epidemic is able to spread in a heterogeneous hypernetwork. The model is subject to the phenomenon of bistability where a disease-free equilibrium and an endemic equilibrium coexist.