Background: Polygonum hydropiper L (PH) was widely used to treat dysentery, gastroenteritis, diarrhea and other diseases. Coptis chinensis (CC) had the effects of clearing dampness-heat, purging fire, and detoxifying. Study confirmed that flavonoids in PH and alkaloids in CC alleviated inflammation to inhibit the development of intestinal inflammation. However, how PH-CC affects UC was unclear. Therefore, the aim of this study is to analyze the mechanism of PH-CC on ulcerative colitis (UC) through network pharmacology and in vivo experiments. Methods: The active ingredients and targets of PH-CC and targets of UC were screened based on related databases. The core targets of PH-CC on UC was predicted by protein-protein interaction network (PPI), and then the Gene Ontology-biological processes (GO-BP) function enrichment analysis was conducted using the Database for Annotation, Visualization and Integrated Discovery (DAVID) database. The binding activity between pyroptosis proteins, core targets and effective ingredients were verified based on molecular docking technology. Finally, combined with the results of network pharmacology and literature research, the mechanism of PH-CC against UC was verified by in vivo experiments. Results: There were 23 active components and 191 potential targets in PH-CC, 5275 targets in UC, and 141 co-targets. GO-BP functional analysis of 141 co-targets showed that the first 20 biological processes were closely related to inflammation and lipopolysaccharide (LPS) stimulation. Furthermore, core targets had good binding activity with the corresponding compounds. Animal experiment indicated that PH-CC effectively prevented weight loss in UC mice, reduced the disease activity index (DAI) score, maintained colon length, suppressed myeloperoxidase (MPO) activity, inhibited pyroptosis protein expression, and downregulated the levels of IL-18 and IL-1\beta to alleviate intestinal inflammation. Conclusions: The results of network pharmacology and animal experiments showed that PH-CC suppressed the inflammatory response, restored colon morphology, and inhibited pyroptosis in UC mice. Thus, PH-CC may improve UC by regulating the NOD-like receptor protein domain 3 (NLRP3)/Caspase-1 signaling pathway.