Amphipods are one of the major invertebrate groups and spreading among marine macro-algae in the intertidal zone at Ras Mohamed Protectorate. But, very scarce information is available about amphipod species presence, their abundance and the factors affecting their distribution. So the present work aimed to study the effect of some physical factors on the abundance and diversity of amphipod species inhabited macro-algal hosts. Through the present work, samples were collected seasonally from three sites inside this protectorate. Results indicated that 2 macro-algal species of red algae were collected from these three sites. The algal species fluctuated in different sites. 16 of the amphipod species were recorded inhabiting them. The highest abundance and diversity of amphipod species were recorded at Yollanda beach. Some amphipod species were found at the site and not recorded at other sites. The diversity and abundance of these amphipod species were fluctuated between sites depending on many physical factors such as wave exposure, the shape of algal hosts, surrounding habitats and environments