Agrocybe aegerita is widely popular for its umami taste. This study utilized five enzymes to hydrolyze the non-volatile taste active compounds extracted from A. aegerita, including inorganic ions, organic acids, soluble sugars, free amino acids, 5′-nucleotides, and small peptides. The taste activity value (TAV) was used to measure the non-volatile taste active components, while the synergistic effects of umami were determined using equivalent umami concentration (EUC). The results showed that the protamex-treated hydrolysate had the highest umami sensory score (7.03) and EUC value (1039.475 ± 2.673) with the most low-molecular-weight peptides (<1 KDa) and soluble sugars, conferring the best overall flavor characteristics. Furthermore, a positive correlation was found between the EUC values and umami sensory scores and acceptability. Overall, the results showed that the protamex-treated A. aegerita hydrolysate had the highest umami taste and acceptability. Thus, this study provides more information for further studies on the umami compounds of A. aegerita and a theoretical basis for the development and utilization of A. aegerita as a condiment.