To investigate the clinical utility of small airway function indices for early identification of GOLD stage 0 chronic obstructive pulmonary disease (COPD). This retrospective study enrolled 137 participants at our institution between January 2017 and December 2018, comprising 40 healthy controls, 46 individuals with GOLD stage 0 COPD, and 51 patients with established COPD. Pulmonary function was assessed using the PowerCube spirometry system (GANSHORN, Germany). Parameters evaluated included forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, and small airway function indicators. The COPD cohort exhibited significantly lower values across all lung function measures compared to the other two groups, particularly for dynamic lung volume parameters such as FEV1%predicted and FEV1/FVC%. Small airway function indices, including FEV3%predicted, FEF75%predicted, FEF50%predicted, FEF25%predicted, and MMEF%predicted, were markedly decreased in the COPD group (all -values <0.001). Receiver operating characteristic (ROC) curve analysis demonstrated that MMEF/FVC% and FEV3/FVC% had high diagnostic accuracy for COPD, with MMEF/FVC% exhibiting the optimal sensitivity and specificity. Small airway function indices, especially MMEF/FVC%, can serve as effective tools for early identification of GOLD stage 0 COPD. Incorporation of these findings into clinical practice may facilitate early diagnosis and intervention, thereby improving treatment outcomes and patient quality of life.