Oncolytic virus therapy belongs to immunotherapy. It can achieve the purpose of killing tumors by virus-specific infection and activating tumor immunity. Compared with traditional therapies, it has the advantages of safety, efficiency, and less side effects. A variety of viruses have been studied, and commonly used viruses include adenovirus, vaccinia virus, herpes virus, reovirus, parvovirus, Newcastle disease virus, Coxsackie virus, etc. for oncolytic therapy, and have been used in clinical and achieved good therapeutic effect. With the continuous development of oncolytic viruses, there are currently 4 oncolytic viruses approved for marketing: Rigvir?, Oncorine?, Imlygic? and Delytact?. Currently many viruses used in tumor treatment. Since the influenza virus were first discovered in the 1900s as a “beneficial” virus to alleviate leukemia, there have been studies that prove that influenza viruses have the ability to kill tumor cells. Researchers have made many attempts in the process of fighting influenza. The process of developing inactivated vaccines, live attenuated vaccines, and subunit recombinant influenza vaccines accumulated valuable experience for further building oncolytic viruses. Influenza viruses were one of the first viruses to be used in tumor treatment. With the development of molecular biology, it is now possible to artificially intervene in many of the traits of viruses. The mechanism of oncolytic influenza virus become more and more in-depth, and the current mode of action of oncolytic influenza virus can be summarized as the following 3 points: (1) the virus directly lyses tumor cells; (2) viruses activate immunity to kill tumor cells; (3) viruses expressing exogenous genes as vectors improves both of these abilities. In this review, the modified influenza virus has stronger selectivity for pancreatic enzymes secreted by tumor cells with interferon-deficient RAS mutations to improve tumor targeting. The single-chain antibody encoding CTLA-4 or HER-2 enhances the anticancer specificity of influenza virus and acts as the carrier of foreign genes IL-2, IL-15, GM-CSF and anti-PD-1 to activate immunity are reviewed.