Acid-base combination is used in some cases expecially after restricted enrichment, and has created many lignocellulose-degrading communities. While how it worked is not well understood. In this study, compost was used as inoculum source. Induced community structure changes were analyzed with high throughput sequencing to elucidate the formation processes and determine the mechanisms of acid-base combination. We found that after restricted enrichment, retaining primarily bacteria not only included that could decompose and utilize lignocellulose, such as Clostridium and Pseudomonas, but also synergistic microbiota such as Pseudoxanomonas and Alkalobacillaceae. When the proportion of these two types of bacteria was not balanced, the degradation ability of the microbial community was low or pH changes of it did not compound regular changes , which maybe lead to the failure of restricted enrichment. Microbial communities were re-constituted by acid-base combination, whereby the degrading and synergistic strains were adjusted to a more appropriate proportion. Acid-base combination xed the instability of microbial communities caused by randomness of restrictive screening enrichment. In this study, the mechanism of acid-base combination was analyzed, which enriched the theoretical system of restricted culture, and provided an effective and controllable technical method for obtaining high-quality lignocellulose-degrading microbial community resources.