Background Post-COVID-19 pulmonary fibrosis is a significant long-term respiratory morbidity affecting patients’ respiratory health. This study aims to investigate the incidence, clinical characteristics, and acute-phase risk factors for pulmonary fibrosis in COVID-19 patients. Additionally, it evaluates their pulmonary function and chest CT outcomes to provide clinical evidence for early intervention and prevention. Methods We retrospectively analyzed 595 patients hospitalized for COVID-19 from January 2022 to July 2023. Patients were divided into fibrosis and nonfibrosis groups on the basis of imaging changes. Baseline data, including demographics, disease severity, laboratory indicators, and chest imaging characteristics, were collected. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors for pulmonary fibrosis. Pulmonary function and chest CT follow-ups were conducted for the fibrosis group. The data were processed via SPSS 26.0, with P < 0.05 considered statistically significant. Results The incidence of pulmonary fibrosis was 4.37%, with 2.08% in moderate cases and 8.22% in severe cases. Significant differences were found between the fibrosis and nonfibrosis groups in sex; disease severity; NLR; ALB and LDH levels; and percentages of lung reticular lesions, consolidations, and GGOs (P < 0.05). Multivariate analysis revealed LDH (OR = 1.004, 95% CI 1.000–1.007, P = 0.035), ALB (OR = 0.871, 95% CI 0.778–0.974, P = 0.015), lung reticular lesion volume (OR = 1.116, 95% CI 1.040–1.199, P = 0.002), and lung consolidation volume (OR = 1.131, 95% CI 1.012–1.264, P = 0.030) as independent risk factors. The follow-up results revealed significant improvements in pulmonary function, specifically in the FVC%, FEV1%, and DLCO%, but not in the FEV1/FVC. Quantitative chest CT analysis revealed significant differences in lung reticular lesions, consolidation, and GGO volumes but no significant difference in honeycomb volume. Conclusions The incidence of pulmonary fibrosis post-COVID-19 increases with disease severity. LDH, ALB, lung reticular lesions, and consolidation volume are independent risk factors for Patients with fibrosis.