Phage display is a widely used gene engineering high technology. Through the display of exogenous peptides or proteins fused specific coat protein on the surface of phages, it is possible to construct proteins or peptides libraries and screen interesting proteins, peptides and antibodies successfully. Most commonly used phage display technology is phagemid/helper phage system, in which helper phages are essential for the replication and assembly of phagemid particles. In this review, in combination with the newest research dynamic status, we summarize phagemid/helper phage double-genome system. We mainly emphasized the features and mutation mechanisms of different helper phages. We also made some prospects for the future directions, in the meanwhile, we also expect that our experience can provide some help for further maturity of the technology.