A novel Alteromonas phage JH01, with the host strain identified to be Alteromonas marina SW-47(T), was isolated from the Qingdao coast during the summer of 2017. Transmission electron microscopy analysis showed that phage JH01 can be categorized into the Siphoviridae family, with an icosahedral head of 62 ± 5 nm and a long contractile tail of 254 ± 10 nm. The bioinformatic analysis shows that this phage consists of a linear, double-stranded 46,500 bp DNA molecule with a GC content of 44.39%, and 58 ORFs with no tRNA genes. The ORFs are classified into four groups, including phage packaging, phage structure, DNA replication and regulation, and hypothetical protein. The phylogenetic tree, constructed using neighbor-joining analysis, shows that phage JH01 has altitudinal homology with some Vibrio and Pseudoalteromonas phage B8b. Comparative analysis reveals the high similarity between phage JH01 and phage B8b. Additionally, our study of phage JH01 provides useful information for further research on the interaction between Alteromonas phages and their hosts.