The effects of mechanical damage on nutritional compositions of fresh-cut potatoes into half averagely have been investigated. In particular, phenolic compouds, polyphenol oxidase (PPO) activities in 2.5mm (surface layer) and 5.0 mm (inner layer from surface) in depth from injury site of fresh-cut potatoes were monitored during storage for 4 days at 5°C. Some chemical index associated with the ripening stage of the product (titrable acidity and soluble solids content) were also evaluated. As a consequence of mechanical damage, The titrable acidity content of the fresh-cut potatoes drastic decrease (from 0.35% to 0.26%) in cut surface and (from 0.35% to 0.237%) in inner surface 1 day later during storage, soluble solids content from the surface layer potato declined from 4.53 Brix% to 2.24 Brix%. Phenolic compounds content climbed up to 2.839OD280/gFW within 1day and declined to 2.696OD280/gFW after 2 days. PPO activity tend to go up in cut surface(from 20 to 29.6 OD398nmmin-1g-1FW) and inner surface (from 20 to 29.56 OD398nmmin-1g-1FW) 2 days later during storage.