Abstract: Enzymatic pretreatment combined with a solvent-free microwave method was used to extract essential oil from fresh Cirsium setosum. The yield of essential oil was used as the evaluation index, and the extraction process of essential oil was optimized through response surface methodology based on single-factor experiments. The composition of essential oils extracted by different extraction methods was analyzed by infrared, gas chromatography-mass spectrometry (GC-MS), scanning electron microscopy, and thermogravimetry. The antioxidant capacity of the extracted oils was evaluated in terms of the scavenging ability of DPPH free radicals, hydroxyl free radicals, ABTS⁺ free radicals, and the iron-reduction capacity. The results showed that the optimal process conditions for extracting fresh Cirsium setosum essential oil by enzymatic pretreatment solvent-free microwave method were enzyme mixing ratio (cellulase:pectinase) 2:1, enzyme addition amount 1.5%, enzymatic hydrolysis time 1.5 h, microwave power 560 W, extraction time 40 min. Under these conditions, the essential oil yield was 0.17%±0.005%. The essential oil obtained by enzymatic pretreatment solvent-free microwave method contains a higher proportion of oxygen-containing compounds. Compared with the essential oil obtained by water extraction reflux method, the content increment of its essential oil components from high to low is n-hexadecanoic acid (36.50%), 2-methyltetradecane (3.82%), (Z)-9-octadecanamide (3.03%), 2,7-octadiene-1-ol (2.40%), allyl pentadecyl oxalate (1.81%), (Z)-1,5,9-undecatriene-2,6,10-trimethyl (1.55%), and (E)-2-decen-1-ol (1.04%). In addition, fresh Cirsium setosum essential oil extracted by enzymatic pretreatment solvent-free microwave method showed stronger antioxidant activity. Therefore, enzymatic pretreatment solvent-free microwave method is a green and effective technology for obtaining high-yield and high-quality essential oils from fresh Cirsium setosum, providing basic data and support for the extraction and development of Cirsium setosum essential oils.