Staphylococcus aureus is a gram-positive pathogen. The clinical isolates are usually resistant to multiple antibiotics. Therefore, it is of great significance to find specific phages with high efficiency and broad host spectrum for the treatment of clinical drug-resistant S. aureus infection. Using S. aureus K84 as the host, lytic phage SAK84P was isolated from sewage. The phage has a hexagonal head with 112 nm in diameter and a contractile tail with 200 nm in length. Based on the morphology, the phage can be classified as myovirus. It has the optimal growth pH between 5.0～7.0, growth temperature between 37～50 ℃, the one-step growth curve shows its duration time is 20 min, and burst size of 100 PFU/cell. Whole genome sequencing shows the phage has a total genome length of 141 535 bp with 30% of GC content, and encodes 224 open reading frames and 4 tRNA genes. The phylogenetic tree diagram shows that the phage belongs to the Kayvirus genus in the family of Herelleviridae. The results also shows that phage SAK84P has a broad host range and can lyse multiple clinic isolates of S. aureus with a high activity. Genome annotations indicate no known resistance genes or virulence genesinthe genome of phage SAK84P, suggesting its potential for treatment of clinical multidrug-resistant S. aureus infection.