Poxvirus is one of the most serious zoonosis pathogens, which has largest genome and broadest host spectrum. With the development of molecular biology, functional genomics, and immunology-related technology, the interactions between pathogen and the host, particularly a large array of host range factors and their functions have been increasingly discovered. These findings provide references for the molecular basis of poxvirus tissue tropism and host specificity. This review focus on the introduction of host range factors in major members of Chordopoxvirinae to highlight the understanding of the mechanisms of molecular genetic evolution, the host tropism, and cross-species infection of poxviruses.