Pulmonary fibrosis (PF) is a lethal lung disease characterized by recurrent alveolar epithelial injury, persistent fibroblast activation, and excessive extracellular matrix (ECM) deposition. Although Pirfenidone and Nintedanib have been implemented in clinical practice, they only delay rather than reverse disease progression. The core bottleneck lies in the epigenetically-mediated "pathological persistence" or "pathogenic memory" of activated fibroblasts. Recently, metabolic reprogramming—specifically lactate accumulation resulting from the "Warburg effect"—has been identified as a critical driver of fibrosis evolution. The discovery of protein lactylation (Kla) in 2019 provided a novel perspective for understanding this process. As a nascent post-translational modification (PTM), lactylation acts as a "metabolic-epigenetic switch," solidifying transient metabolic disturbances into enduring gene transcription programs by remodeling the biochemical signatures of histones and non-histone proteins. This review systematically elucidates the biochemical regulatory system of lactylation and its molecular mechanisms in locking fibroblast activation, mediating "metabolic-immune" paracrine crosstalk, and driving oxidative stress and mechanical feedback loops. [ ]By providing an in-depth analysis of the logic behind lactylation-mediated "pathogenic memory" formation, this article aims to reveal the unique value of targeting the lactate metabolic axis in breaking the self-sustaining loops of fibrosis, offering prospective theoretical guidance and translational insights for the development of novel anti-fibrotic drugs with "memory-erasing" capabilities.