Objective: To investigate the clinical and immunological features of cardiac involvement in patients with anti-synthetase syndrome (ASS). Methods: In the study, 96 patients diagnosed with ASS hospitalized in the Department of Rheumatology and Immunology, Peking University People’s Hospital from April 2003 to November 2020 were included. The patients were divided into two groups according to whether they were accompanied with cardiac involvement. Demographic features, clinical characteristics (Gottron’s sign/papules, muscle damage, etc.), comorbidities, laboratory indices (creatine kinase, inflammatory indicators, immunoglobulin, complement, lymphocyte subset, autoantibodies, etc.) were collected and the differences between the two groups were analyzed statistically. Results: The prevalence of cardiac involvement in the patients with ASS was 25.0% (24/96). The ASS patients complicated with cardiac involvement presented with elevated cardiac troponin I (cTnI, 75.0%, 18/24), pericardial effusion (33.3%, 8/24), reduction of left ventricular function (33.3%, 8/24) and valves regurgitation (33.3%, 8/24). The age of onset of the patients with cardiac involvement was older than that of the patients without cardiac involvement [(54.58±10.58) years vs. (48.47±13.22) years, P=0.043). Arthritis was observed less frequently in the patients with cardiac involvement than those without cardiac involvement (37.5% vs. 61.1%, P=0.044). In addition, rapidly progressive interstitial lung disease (54.2% vs. 30.6%, P=0.037) was observed more frequently in the patients with cardiac involvement than those without cardiac involvement. As compared with the ASS patients without cardiac involvement, C-reactive protein (CRP) [(13.55 (8.96, 38.35) mg/L vs. 4.60 (1.37, 17.40) mg/L, P=0.001], and lactate dehydrogenase (LDH) [408.0 (255.0, 587.0) U/L vs. 259.5 (189.8, 393.8) U/L, P=0.007] were significantly higher in the patients with cardiac involvement. Anti-Ro-52 antibody was detected more commonly in the ASS patients with cardiac involvement compared with the patients without cardiac involvement (91.7% vs. 69.4%, P=0.029). No significant differences were found in the comorbidities, alanine transaminase (ALT), aspartate transaminase (AST), creatine kinase (CK), erythrocyte sedimentation rate (ESR), ferritin (Fer), immunoglobulin G (IgG), complement 3 (C3), complement 4 (C4), lymphocyte subset between the two groups. Conclusion: Cardiac involvement is common in ASS, mainly manifested as myocardial damage. It is necessary to be aware of cardiac complications in patients with elevated CRP, elevated LDH and positive anti-Ro-52 antibody.