This study aimed to systematically compare the nutritional composition and taste activity value in the muscle of Macrobrachium rosenbergii cultured in saline-alkaline water versus freshwater. Basic nutrients， minerals， fatty acids， and amino acids were analyzed to evaluate nutritional differences. Flavor characteristics were analyzed through taste activity value （TAV）. No significant differences were observed in moisture， crude protein， crude fat， or ash content between the two groups. However， the saline-alkali group exhibited significantly higher levels of Na， Mg， P， Fe， Cu and Zn（P<0.05）. The EPA and DHA contents in the saline-alkali group were （15.69 ± 0.70）% and （8.95 ± 0.49）%， respectively， significantly exceeding those in the freshwater group （14.12 ± 0.66）% and （5.25 ± 0.31）% （P<0.05）. The EAAI score of the saline-alkali group （84.89） was slightly higher than that of the freshwater group （83.83）. Taste analysis revealed that TAV values of Glu， Gly， Ala， Arg， AMP， and IMP in the saline-alkali group （1.83， 2.56， 2.15， 5.65， 1.64， 8.14） were higher than those in the freshwater group （1.38， 1.89， 2.03， 4.17， 1.04， 4.64）， whereas the TAV of His （2.76） was lower. Saline-alkali aquaculture enhances mineral accumulation， polyunsaturated fatty acid content， and umami-related compounds in M. rosenbergii， demonstrating superior nutritional and flavor qualities compared to freshwater systems. This study provides a scientific basis for optimizing saline-alkali land utilization in aquaculture.