Waste vinegar residue (WVR) is a by-product of vinegar processing by solid-state fermentation. In this study, two experiments were conducted to determine chemical composition and ruminal degradability of WVR and whether WVR can be used as a feedstuff for ruminants. In Experiment 1, 14 WVR samples were incubated in the rumen of three Inner Mongolia White Cashmere Goats to determine the in sacco ruminal degradability parameters for DM, crude protein (CP) and neutral detergent fibre (NDF). The NDF, CP and ether extract (EE) contents of the WVR samples were 796.6, 125.2 and 93.3 g/kg, respectively. The greatest variation was observed for lactic acid, which ranged from 150.39 to 4391.12 mg/kg with an average of 1023.84 mg/kg. The average A, B and C fractions of DM for the 14 samples of WVR were 122, 350, and 528 g/kg, respectively. The effective degradability of DM, CP and NDF were 275, 550 and 211 g/kg, respectively. In Experiment 2, the in sacco degradation parameters for DM, CP and NDF of Chinese leymus, corn stalk and WVR were evaluated in a 3 × 3 Latin-square design. The rapidly degradable fraction of the DM and NDF for WVR was significantly (P < 0.01) greater than that of Chinese leymus and corn stalk. No difference in rumen-degraded DM, rumen-degraded CP and rumen-degraded NDF was found between Chinese leymus and WVR (P > 0.05). It is concluded that, WVR is not well digested ruminally but is a good source of protein for ruminants giving it value as an ingredient in ruminant diets.