Objective: In order to improve the utilization rate and higher value application of pomelo peel， the surimi products with the addition of pomelo peel powder were developed， and the effects of pomelo peel powder with different particle sizes on the quality characteristics and protein secondary structure of fish balls were studied. Methods: Pomelo peel powder with different particle size were prepared by size sieving and jet-milling. The dietary fiber was used as a control， the changes of water holding capacity， gel strength， texture and color of frozen and frozen fish balls with pomelo peel powder at different sizes were investigated. The change law of protein secondary structure of fish balls affected by pomelo peel powder with different sizes was further analyzed by FT-IR. Results: Compared with the blank group， after cold storage for 24 h， the water holding capacity， gel strength， hardness and chewiness of fish balls decreased with different sizes of pomelo peel powder and dietary fiber (P < 0.05). After frozen storage for 7 d， the water holding capacity of the fish balls with pomelo peel powder of particle size < 150 μm was significantly higher than that of the blank group and the fish balls with dietary fiber (P < 0.05)， of which the gel strength and springiness were not significantly different from those of the blank group (P ≥ 0.05). With particle size of pomelo peel powder decreased， the enhancement of water holding capacity of the fish balls was weaken， and the hardness and chewiness decreased significantly. The results of FTIR spectrum analysis of frozen fish balls showed that the addition of pomelo peel powder with size < 150 μm resulted in the increase of the β-sheet structure in fish balls， enhancing the formation of the more ordered structure of protein gel. However， such change of molecular structure did not lead to the corresponding change of macroscopic gel properties and hardness. Conclusion: Via the particle size sieving， the larger particles of pomelo peel powder (< 150 μm) were more suitable for the production of frozen fish balls， which could significantly improve the water holding capacity of fish balls. Different particle sizes of pomelo peel powder could significantly affect the protein secondary structure of frozen fish balls， however， the mechanism of association between the secondary structure and processing characteristics such as water retention， gel strength and texture of fish balls remains to be further explored.