The countershading formed by deep body color of dorsal surface and shallow body color of venteral surface is beneficial to avoid enemies and prey, and is more common in marine fishes. In order to understand the ecological adaptation of the marine bony fishes and the formation of pigment cells in the dorsal and venter surface, six kinds of marine pelagic fishes and five kinds of demersal fishes were collected, respectively. The results show that no matter the marine pelagic fishes (including Megalaspis cordyla, Hemiramphus far, Seriola quinqueradiata, Trachurus japonicus, Decapterus maruadsi, Scomberomorus niphonius) or marine demersal fishes (Muraenesox cinereus, Synechogobius ommaturus, Trichiurus japonicus, Aluterus monoceros, Harpadon nehereus). Both melanocytes and xanthophores are more in dorsal than in venter, and the difference between dorsal and venter is significant. Compared to the offshore demersal fishes, the countershading in these offshore pelagic fishes is more obvious. The iridocystes are present in both the skins of dorsal and venter, in the venter of marine demersal fishes most of pigments are iridocystes. There are few of the erythrophores in the demersal fishes, but more erythrophores can be seen in marine pelagic fishes. In summary, the investigation shows that the countershading mainly depends on the amounts of both melanocytes and xanthophores in the dorsal skin, and the venter color is related to iridocystes in marine bony fishes.