Pomelo (Citrus grandis (L.) Osbeck) is the largest citrus fruit in Thailand, whichpomelo juice is commercially produced during the pomelo juice extraction process. After extraction of the juice, the number of by-products that was produced  could be a potential source of functional dietary fiber.The objective of this studywas to evaluate extraction methods of dietary fiber from pomelo juice byproducts for functional foods and particlesize distribution (150, 180, 250 and 425 mm)by pomelo pulp powder (PPP) that was prepared by simply air drying, milling, sieving and grinding. For pomelo pulp dietary fiber powder (PPDFP), the PPP was treated with NaOH and ethanol to remove protein and fat, respectively. After that, analysis ofphysicochemical and functional propertiesof PPP and PPDFPfound that the PPDFP was richer in total dietary fiber (92.04%), especially insoluble dietary fiber (91.93%). Water holding capacity (WHC) and oil holding capacity (OHC) of PPDFP were higher than those of PPP. Components that can contribute to the bitter flavor of the powders, limonin, naringin and naringenin were considerably reduced in PPDFP, particularly limonin was totally eliminated. Also, the porous structure of PPDFP may facilitate its use in food processing compared to the more sheet-like structure of PPP. The optimum particle size was 150 mmthat resulted in powders with increased WHC and OHC. From the above data, it was concluded that the PPDFP was a good source for food dietary fibers that could be used as a functional ingredient in fiber rich food products.