Citrus is an important part of fruit family. It belonging to the family Rutaceae, which include fruits such as orange, mandarin, lime, lemon, sour orange and grapefruit, pomelo appear as a well known promising source of multiple beneficial nutrients for human beings. Processing of citrus by-products (peel, pulp, and seed) potentially represents a rich source of phenolic compounds and dietary fiber, by consumption of citrus fruit the large amount of peel waste produced. These citrus fruit residues, which are generally discarded as waste in the environment, they can act as potential nutraceutical resources. Such comprehensive Utilization of Citrus By-products provides comprehensive knowledge and information on the development and utilization of citrus by-products, including (types, preparation, and determination) of their main functional components. One of the most popular fruits in the world, from the point of processing is citrus fruits by which produces citrus peel, a primary by-product. Current statuses of citrus peel pollute the environment and waste resources so eco-friendly solutions are sought. This review systematically summarized the knowledge of utilization of citrus peel, which generally discarded as waste by consumer after consumption of fruit.