To inquire the correlation of cathepsins activities and texture and myofibrillar protein degradation of tilapia fillets during iced storage, the changes of cathepsins B, H, L and D activities over a period of iced storage were measured.And these variation trends of texture of fillets as well as myofibrillar protein with iced time and correlation among them were also determined.The results showed that cathepsins B and D activities presented a fluctuatingly upgraded tendency on the whole, and cathepsins L, sum of B and L activities presented a first descending and then upgraded tendency.A highly significant positive correlation was observed between cathepsins B and sum of B and L activities and iced storage period.Through the duration of storage, changing scale of cathepsin H activity was small.Myofibrillar protein had a maximum content on the iced 2^nd day, and its overall variation trend showed a significant negative correlation with iced time.The SDS-PAGE pattern showed that myosin heavy chain degraded obviously, while actin and tropomyosin had no remarkable changes, and α-actinin degraded gradually in the first iced four days.Texture indices including hardness, gumminess and chewiness on the whole presented a fluctuating tendency, and cohesiveness as well as springiness did not change remarkably through the iced storage, whereas adhesiveness and adhesive force increased gradually two days after iced storage.The correlation analysis of cathepsins activities and texture as well as myofibrillar protein content indicated that cathepsin B activity was largely related to springiness and myofibrillar protein content, and cathepsins L and D presented a significant correlation with hardness, gumminess and chewiness.Cathepsins L and D were the most likely to be directly involved in the postmortem softening of tilapia fillets muscle during iced storage.Lysosomal cathepsins may have participated jointly in autolysis of fish.