The objective of the research was to learn the understanding as well as musyarakah contract in fishermen and the perspective of Islamic Law towards musyarakah contract made by fishermen at Gane Barat Sub-District. In this research, the researcher used qualitative method with qualitative descriptive research using field research. The data used were primary and secondary. The primary data were obtained through interview, observation, and documentation. The secondary data were obtained through documentation. The data obtained were examined using data source triangulation. The data were then analyzed using Miles and Huberman in which the data were reduced, presented, and verified to make conclusion and to answer the research question. The result of the research indicated that the understanding of the cooperation concept conducted by fishermen in Gane Barat Sub-District was still limited. This was because of education factor. Meanwhile, the application of cooperation between rumpon (rompong) fishermen and pajeko (fish boat) fishermen still used the existing local customs or habits. This law has been applied by generations and becomes the basic guidance in conducting cooperation. Meanwhile, the application of fishermen’s cooperation contract has fulfilled the rules and requirement.