This study was carried out to investigate the effects of substitution of fermented king oyster mushroom (P. eryngii) by-products diet on pork meat quality characteristics, during the storage. A mixture of 40% king oyster mushroom by-products, 28% soybean meal and 20% corn was fermented for 10 d, and the basal diet was then substituted by the fermented diet mixture of up to 20, 50 and 80%, respectively. A total of 96 pigs were fed experimental diet (8 pigs per pen× 4 diets × 3 replication), and eight longissiumus (LD) per treatment were collected, when each swine reached to 110 kg of body weight. The Warner-Bratzler shear forces and cooking loss were significantly lowered in the treatments, while crude protein content and water holding capacity significantly (p<0.05) increased in the treatments than in the control group. The volatile basic nitrogen (VBN), at 1 d of storage, was lower in the treatments, while texture profiles and sensory evaluation did not differ between the control and the treatments (p>0.05). The pH, thiobarbituric acid reactive substances (TBARS), VBN and meat color in all treatments were increased as storage increased. Fermented king oyster mushroom by-products diet effects on lightness (CIE L * ), yellowness (CIE b * ) and chroma were determined, when LD muscles in T2 and T3 treatments were higher (p<0.05), up to 7 d (p<0.05). Therefore, the results indicate that the substitution of the fermented king oyster mushroom by-products diet to swine diet influenced the quality of the meat and it may be an economically valuable ingredient.