The invention relates to functions of genes of pseudomonas aeruginosa and an application of the genes, wherein the gene BN889_05221, the gene PA0243, the gene PA3808, the gene PA1993 and the gene PA1115 of pseudomonas aeruginosa are the necessary host genes of phage infection, and are used for screening the relevant medicines for inhibiting the phage infection. According to the invention, through the study on the relevant host genes of phage infection, a molecular mechanism for the interaction between phage and host bacteria can be well understood, therefore, a theoretical basis is provided for the treatment on the phage, meanwhile, new target genes related to virus infection can be found, and assistance is provided for screening antiviral drugs.