Proteins are one of the types of biological macromolecules that were made of the smaller subunit called amino acids. Proteins are very diverse and are the basis of life living organisms.These biological molecules have the role of construction and other important functions, such as hormonal, storage, protection and safety inside of living creatures. Collagen is a protein in connective tissue that its fibers would determine the shape of the tissue and maintain it. Collagen is widely used in medical and non-medical including gelatin construction, cosmetics, heart surgery and pharmaceutical industry. Increase in world population and the need for protein cause special attention to marine food sources. The other hand, jellyfish is full of collagen. Therefore, extraction of collagen from jellyfish has attracted a lot of attention of researchers. In general, separation of dissolved and undissolved materials from diluted solutions is a difficult task. This problem becomes more serious for substances such as proteins and enzymes. That is due to the fact that these materials are sensitive to changes in operating conditions such as temperature. Method of acid and pepsin digestion commonly is used in extraction of collagen. Since the objective of this study is to extract collagen from jellyfish with high efficiency, a combination of three methods of acid, pepsin and salting out for extraction and purification of collagen from Aurelia sp species jellyfish was used. According to pervious research, the extraction efficiency increases with increasing the percentage of pepsin. So in this thesis, pepsin 0.3% ( ) was used in the method pepsin. The yield of the ASC was 14% (dry weight) and that of the PSC was 6% (dry weight). The amount of jellyfish protein and purified collagens was measured by using a spectrophotometer. The protein of the jellyfish, the acid-soluble collagens (ASC) and pepsin-solubilized collagens (PSC) were 19.65 , 692.8 and 723.4 , respectively. In order to evaluation of collagen type and the purification and the lack of change the nature of the collagen, electrophoresis was used. In electrophoresis patterns, the acidic and pepsin collagen was observed (? 1 ) 3 chain that was similar the acidic and pepsin collagen from jellyfish C.nozakii. Atomic absorption spectrometry was used to determine the chemical elements. The results showed that the amount of Pb was less than detection limit, Cd exceeded limit and the amount of Fe, Zn and Cu was less than the limit. More of Cd may be due to entering industrial wastewater to the Bushehr Persian Gulf. To check the denaturation temperature, the viscometer was used. The results showed that the denaturation temperature was about 29 ?C. The results showed that the denaturation temperature depends on jellyfish species and the ambient temperature that jellyfish lives. To study the structure of the collagen extracted scanning electron microscope images was used. Scanning electron microscope images showed that collagen is formed of fibers with different diameters with sheets. To determine the secondary structure of proteins and peptides and functional group present in the sample, FT-IR spectra was used. Collagen IR spectra showed that pepsin digestion in very small amount causes fragmentation of triple helix collagen. Finally, the results of FT-IR and electrophoresis sho