We have defined the biochemical composition of the carcass meat of muskrat, including the content of the amino acids, lipids, and saturated and unsaturated fatty acids. The moisture, crude proteins, fatty acid, and ash were 74.6, 23.2, 1.2, and 0.92%, respectively. The average amount of calories was 478 kJ per 100 g meat. We separated 17 amino acids using reversed-phase high-performance liquid chromatography (RP-HPLC) analysis. The fat content was low in both male and female invasive muskrats. The aliphatic tails of the fatty acids range from 16 to 18 carbons. The saturated palmitic (C16:0) and stearic acids (C18:0), and unsaturated oleic (C18:1) and linoleic (C18:2), and linolenic acids (C18:3) were extracted. Even though some of the western provinces in Mongolia applied the carcass meat of the muskrats for treatment against kidney disease in traditional medicine, the scientific proof is still unclear.