The study aimed to evaluate the effects of Allium mongolicum Regel (AMR) and its water‐ and fat‐soluble extracts on the quality of fermented mutton sausages. Sausages were produced with mutton and fat. Four treatments: CO, without Allium mongolicum Regel and its extracts, used as control; AMR with Allium mongolicum Regel; AWE with water‐soluble extract of Allium mongolicum Regel; and AFE with liposoluble extract from Allium mongolicum Regel, were produced and analyzed for pH, water activity (aw), free amino acids, fatty acids, and volatiles were, respectively, in fermented mutton sausages during processing (0, 2, 5, and 7 days). The results showed that the pH values of the liposoluble extract from Allium mongolicum Regel (AFE), respectively, are lower than that of sample CO at the end of fermentation and ripening. The aw in all group of sausages significantly dropped to 0.88 at the end of ripening (Day 7). Adding Allium mongolicum Regel and its water‐soluble extract can improve the serine (SER) content of fermented mutton sausage. The contents of five essential amino acids (EAA) were added when adding Allium mongolicum Regel and its fat‐soluble extract. The total fatty acid (TFA) in the treatments increased during drying and ripening. The addition of Allium mongolicum Regel and its extract can increase the content of volatile flavor substances such as 3‐hydroxy‐2‐butanone, 3‐methylbutyraldehyde, hexanal, octanal, and nonanal at the later stage of maturity, so as to improve the flavor substances in fermented mutton sausage. Water‐soluble extract of Allium mongolicum Regel (AWE) and AFE treatments had more intense flavor at the end of ripening (Day 7). The flavor of fermented mutton sausage can be improved by adding Allium mongolicum Regel and its extracts into fermented mutton sausage.