Abstract: To improve the undesirable odors such as fishy and smoky smell, and enhance the added value of sea cucumber (Apostichopus japonicus) blanching liquid, we optimized the enzymatic hydrolysis conditions through single-factor and orthogonal experiments, and systematically analyzed the flavor changes by using electronic tongue, high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and headspace solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). The results show that trypsin exhibited the best hydrolysis effect, with the optimal conditions of 50°C, pH 7.0, 5 h, and 5% enzyme dosage. Under these conditions, the hydrolysate achieved sensory scores and degree of hydrolysis of (8.50±0.27) and (19.77±0.37)%, respectively. Flavor analysis reveals that: 1) Electronic tongue detection showed enhanced umami, sweetness, saltiness, and richness, but reduced bitterness, astringency, and sourness; 2) HPLC-MS/MS identified arginine (130.4‰) and glutamic acid (106.7‰) as the main flavor-active amino acids, with significant increases in sweet-tasting amino acids such as serine and threonine; 3) SPME-GC-MS detected 33 volatile compounds, where increased benzothiazole (0→3.79%) contributed meaty, vegetable, and nutty aromas, while decreased 1-octen-3-ol (1.52%→0), p-cresol, amines, and ketones (37.46%→24.64%) effectively reduced off-flavors such as fishy and smoky odors.