In this research, concentrations of heavy metals (Lead, Copper, Cadmium and Mercury) in sediments, muscle tissue of Cynoglossus arel fish and brown Seaweed (Sargassum illicifolium) of five stations from the northern Oman sea that names Jask port (Hormozgan province), Darak port, Pozm port, Chabahar Golf and Goatre port in water of Oman Sea on the Sistan and Balochestan province were measured and compared. For this purpose, samples were randomly collected together with water and sediment from each station in summer 2017. Samples of Sediment was digested by using MOOPAM method and metal were measured by using atomic absorption spectrophotometer (AAS). The average concentration of heavy metal in sediment in northern coasts of Oman Sea for Pb, Cu, Cd and Hg were 3. 38, 13. 61, 0. 21 and 0. 88ppm, muscle tissue 0. 94, 3. 87, 0. 09 and 0. 06 ppm and brown microalgae 0. 01, 7. 40, 0. 07 and 0. 06 ppm respectively (p<0. 05). Nevertheless, the highest mean concentration of lead, Copper and Mercury (13. 65, 20. 21, and 1. 56 respectively) in the sediment of Jask port, and Cadmium (0. 28) in Jask port and Chabahar Golf were observed. Also, investigation of heavy metals in the muscle ofCynoglossus arel fish and brown seaweed showed the highest concentration of lead (2. 73-0. 25), Copper (7. 08-13. 39), Cadmium (0. 26-0. 15) and Mercury (0. 20-0. 16) in the sample of Jask port respectively. Also, the lowest average concentration of these heavy metals in all of samples was recorded in Darak port. In general, our study showed that the concentration of heavy metals in Jask port and Chabahar Golf were significantly higher than other areas. The concentration of heavy metal in the sediments, muscle tissue and brown seaweed in each of five stations had lower in value (except for the copper metal concentration, which was higher than the LAL level) than the acceptable limit suggested by the standard value of WHO, FDA, NHMRC, NOAA, CCME, USEPA and institute of the national standard center of Iran.