Mattress is among the main products of ectopic fermentation system (EFS),however, the research on the data of antibiotic residues in the mattress of EFS and risk assessments of mattress have not been conducted. This study involved a scale survey to assess the levels and distributions of 54 antibiotics residues, including 4 tetracyclines, 19 quinolones, 22 sulfonamides, 3 amphenicols, and 6 macrolides in mattress on 12 swine farm that uses ectopic fermentation systems (EFS) in Zhejiang Province. A total of 25 antibiotics were detected in mattress, and the total residue amount of antibiotics in mattress samples of each farm was 0.77–28.2 g/T. Chlortetracycline had the highest contribution rate, and the residue amount of antibiotics in mattress is not entirely determined by the start-up time of EFS but is related to the use of feed containing antibiotics, medication habits, the level of mattress management, and maintenance methods of EFS. The risk assessments of antibiotics in the mattress were carried out. The results show low risk for soil on swine farm that uses EFS.