Refractory ceramic fibers (RCFs) are increasingly used as heating-insulated materials in various industries . However, toxicological and epidemiological studies focusing on the adverse effects of RCFs were still insufficient, particularly in China . We conducted a cross-sectional study to evaluate comprehensively the associations between occupational exposure to RCFs and respiratory health effects among Chinese workers . We measured and calculated cumulative RCFexposure levels of RCFs workers from the biggest RCFs factory in China . In total, 430 RCF-exposed workers and 121 controls were enrolled in this study . Physical examinations of the respiratory system were performed and serum levels of biomarkers including Clara cell protein 16 (CC16), surfactant protein D (SP-D), transforming growth factor ß1 (TGF-ß1), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were determined among all subjects . RCF exposure workers showed a higher prevalence rate of respiratory symptoms (cough : 11.9 %) and lower levels of small airways function indices (V50% : 82.71 ± 20.01, maximal mid expiratory flow (MMEF)% : 81.08 ± 19.56) compared with the control group (cough : 5.0%, V50% : 90.64 ± 24.36, MMEF% : 88.83 ± 24.22). RCFs workers showed higher levels of TGF-ß1 (31.04 ng/mL) and 8-OHdG (130.72 ng/mL) and lower levels of CC16 (3.68 ng/mL) compared with the controls (TGF-ß1 : 26.63 ng/mL , 8-OHdG : 106.86 ng/mL, CC16 : 5.65 ng/mL). After adjusting for covariates, cumulative RCF exposure levels showed significant positive associations with the levels of TGF-ß1 and 8-OHdG and negative association with the level of CC16 . Occupational RCF exposure could induce adverse respiratory health effects, including cough and small airways damage, which may correlate to the altered levels of lung damage markers (CC16 and TGF-ß1) and oxidative markers (8-OHdG).