Abstract: Peritoneal fibrosis (PF) is an important reason that restricts long-term treatment of peritoneal dialysis (PD). Based on the theory of collateral disease, PF is considered to be an abdominal collateral disease, with dampness as the main pathogenic factor, and collateral qi deficiency and stagnation, toxicity and blood stasis as the core pathogenesis. The peritoneum is chronically exposed to an inflammatory microenvironment induced by non-biocompatible peritoneal dialysis fluid, reflecting the pathogenic mechanism of dampness-induced pathology. The resultant pathological processes, including damage of peritoneal mesothelial cells, accumulation of inflammatory mediators and metabolic products, and angiogenesis—elucidate the scientific connotation of dampness impairing collaterals and inducing deficiency, toxicity, and stasis. On this basis, the treatment principles of invigorating qi, detoxifying, resolving stasis and unblocking collaterals were proposed, and the Qixue Huazheng prescription was formed with Astragalus as the main ingredient and Centella asiatica and Ligusticum wallichii as the compatibility, which provides a reference for the prevention and treatment of PD-related PF by traditional Chinese medicine.