This paper conducts a study of the inhibitory effect of trehalose on the protein denaturation of grass carp frozen surimi. At first, salt-soluble protein, total sulfhydryl, Ca²⁺-ATPase activity and carbonyl group were monitored during the frozen-storage period (12 weeks). When the addition of trehalose was 6%, the inhibitory effect on protein denaturation was the best. Then, the determination of structure characteristics of the group with the addition amount (6%) was conducted after surimi was frozen for six months. Results: the gel strength of the group with best addition amount reached 3 026 g·mm, much higher than the control group (P<0.01). Scanning electron microscope found that ultrafine 3-dimentional network structureof surimi gel was firmer, more compacted and tougher. The trehalose (6%) has an inhibitory effect on the protein denaturation of grass carp frozen surimi，delays the reduction of frozen surimi quality, and has a good application prospect as a potential commercial surimi antifreeze.