The objective of this study was to evaluate the effects of lipopolysaccharide (LPS) dosing on ruminal digestibility and fermentation. Diets were randomly assigned to 6 fermenters in a duplicated 3 × 3 Latin square with three 11-d experimental periods that consisted of 7 d for diet adaptation and 4 d for sample collection. Treatments were control diet (CON); wheat and barley diet (WBD), to induce subacute ruminal acidosis (SARA); and control diet + LPS (LPSD). Fermenters were fed 72 g of DM/d. The forage:concentrate ratio of CON was 65:35. The WBD was achieved by replacing 40% of the DMI of the CON diet with equal amount of ground wheat and barley; the LPS concentration in LPSD was 200,000 EU which was similar to that observed in cows with SARA. The SARA inducing and LPS dosing started at d 8. Ruminal digestibility, VFA, and NH₃-N samples were analyzed in this study. Ruminal pH was measured every hour before SARA induced and every 30 min once ruminal pH went below 5.6. The ruminal pH of WBD was lower than LPSD and CON (P = 0.05), and WBD was able to keep ruminal pH below 5.6 for 240 min every sampling day, successfully inducing SARA. Ruminal pH of LPSD was not different from CON, and both were above 6 for the entire experimental period. Ruminal NDF (P = 0.10), ADF (P = 0.09) and CP (P = 0.06) digestibility of LPSD tended to be lower than that of CON, but not different from WBD. There were no differences on total VFA concentration, molar proportion of propionate, isobutyrate, valerate, and isovalerate among treatments. WBD had the lowest acetate and the highest butyrate and lactate concentrations; however, there were no differences between LPSD and CON. The dynamic patterns of VFA of LPSD stated to be similar to WBD at 6 h after LPS dosing. The WBD had the lowest concentration of NH₃-N while the highest dietary N; however, no differences were observed between LPSD and CON. In conclusion, grain induced SARA model was successfully set up in dual-flow continuous culture system; ruminal LPS dosing tended to decrease ruminal fiber and CP digestion but have no effects on ruminal pH and fermentation in a dual-flow continuous culture system.