Aloididae aloidi was used as raw materials to study the contents of free amino acids, nucleotides and organic acids, and the changes of volatile flavor substances, protein structure and the exogenous enzyme activity of Aloididae aloidi hydrolysates with ultra-high pressure treatment. The results showed that the ultra-high pressure treatment could activate both the flavor protease and compound flavor protease, and the former was activated more strongly. Compared with the normal pressure treatment, ultra-high pressure treatment led to higher contents of free amino acids, succinic acid and monosodium glutamate equivalents in Aloididae aloidi hydrolysates. In addition, ultra-high pressure treatment gave enzymatic hydrolysates better umami and overall flavor, more main volatile substances, and less unpleasant flavor substances, which changed the composition of volatile substances to achieve flavor-enhanced effect. Ultra-high pressure destroyed the protein structure, which could promote the release of flavor amino acids, improve the flavor of the enzymatic hydrolysates, and increase the protein utilization rate. Ultra-high pressure treatment could improve the proteolytic degree and promote the release of flavor amino acid, nucleotides and organic acids by improving the protease activity, especially flavor protease activity, and destroying the protein structure.