A novel Pseudoalteromonas atlantica phage C7 was isolated from the coastal surface water in the Yellow Sea of China using the agar overlay method. Transmission electron microscopy analysis reveals that it belongs to Siphoviridae with a head of 56 nm in diameter and a tail of 102 nm in length. Microbiological characterization suggests that the phage is stable at a range of temperatures (from - 20 to 65 °C) and the optimal pH range is 6-12. One-step growth curve shows a 45-min latent period and a 105-min rise period. Genomic analysis shows that C7 has a linear, double-stranded 42,261-bp DNA molecule with 40.6% GC content and 76 putative open reading frames (ORFs) with one tRNA. The ORFs are classified into six functional groups as follows: hypothetical protein, phage structure, phage packaging, DNA replication and regulation, transcription, and some additional functions. There are many obviously similarities between C7 and a previously published Pseudoalteromonas phage vB_PspS-H40/1 by genomic comparison. This study provides an important data for further research on the interaction between marine bacteriophages and their hosts.