OBJECTIVE: The organizing pneumonia (OP) pattern is the second most common finding in anti-synthase antibody syndrome (ASS), and nonspecific interstitial pneumonia (NSIP) is the most common finding. This study analysed the OP score changes by semiquantitative and quantitative analysis methods and the correlation between the high-resolution computed tomography (HRCT) indexes and the pulmonary function test parameters (PFTs) in ASS patients. METHODS: Data from ASS-OP patients admitted to the respiratory department of Ping Jin Hospital from October 2014 to June 2020 were retrospectively reviewed and analysed. RESULTS: Fourteen ASS-OP patients were recruited for this study. (1) In method-1, the consolidation (CO) score and the mean lung attenuation (MA) of poorly aerated and fibrosis lung fields (MAfibrosis) (r=0.56, P=0.04), the ground-glass opacity (GGO) score and the MA of non-aerated lung fields (MAnonaerated) (r=-0.64, P=0.01), and the CO plus the GGO (CG) score and the MAnonaerated (r=-0.59, P=0.03) of the lung fields had liner correlations. In method-2, the GGO score to the MAnonaerated (r=-0.58, P=0.03), and the CG (r=-0.68, P=0.01) score to the MAnonaerated had liner correlations. The FVC% (r=0.68, P=0.01) and FEV1% (r=0.64, P=0.01) to the MAfibrosis had good linear correlations. (2) Compared to the values before treatment, the CO pattern score, volume and weight percentages of the extracted whole lung volume with attenuation values of the nonaerated area (Vnonated%, Wnonaerated%), the volume of poorly aerated and fibrosis lung tissue (Vfibrosis%, Wfibrosis%), the weight percentages of normal aerated lung (Wnormal%), and the MAfibrosis exhibited significant differences during the 3-6 month follow-up period. CONCLUSION: The GGO and CO scored by the semiquantitative or quantitative analysis methods was similar. The HRCT quantitative analysis parameters showed a good correlation with the PFTs in ASS-OP patients, can provide an accurate OP pattern interpretation, and may be used as a monitoring and therapeutic indicator for ASS-OP patients.