The present invention belongs to the technical field of application of microbial secondary metabolites, and particularly relates to novel use of prodigiosin in resisting potato virus Y. Application of prodigiosin in preparing a medicine for preventing and controlling potato virus Y. The medicine for preventing and controlling the potyvirus is a liquid or solid preparation containing prodigiosin. It is clarified that PVY promotes its own replication and infection by recruiting host factor Hsp70 in the process of infecting the host, realizing virus infection and spread. Hsp70 plays an important role in the infection and replication of plant viruses. Based on the above results, it is further clarified that prodigiosin treatment can significantly increase the ubiquitination level of the plant host, promote the ubiquitination of HSP70 protein of the host, degrade or inhibit the expression of Hsp70 protein, activate the natural immune activity of the host plant.