The quality indexes of hull-less pumpkin seed oil, which were extracted by supercritical CO₂ fluid extraction, were detected according to the national standard. The fatty acid and phytosterol composition were analyzed by gas chromatography-mass spectrome-try (GC-MS). Subsequently, the squalene content of hull-less pumpkin seed oil was measured by high performance liquid chromatogra-phy (HPLC). Compared with grape seed oil and flaxseed oil, the scavenging activities for DPPH· and ABTS free radical of hull-less pumpkin seed oil were estimated. The results indicated that the hull-less pumpkin seed oil extracted by supercritical CO₂ fluid extraction was according with the food industry standard LS/T 3250—2017 《pumpkin seed oil》. The hull-less pumpkin seed oil mainly contained 4 kinds of unsaturated fatty acid with a total content of 74.73%, including the cis-monounsaturated fatty acids and polyunsaturated fatty acids, with the content of 29.14%, 45.54%, respectively. The contents of β-sitosterol and △-7 phytosterol were 30.75%, 10.77%, respectively. Squalene in hull-less pumpkin seed oil was 5 490 μg/g, up to 80 times of grape seed oil and 279 times of flaxseed oil. The antioxidant activities of hull-less pumpkin seed oil were positively correlated with its concentration. For the hull-less pumpkin seed oil, its ability to scavenge DPPH· free radical (IC₅₀ 16.14 mg/mL) was better than that of grape seed oil and flaxseed oil, and the ability of scavenging ABTS free radical was equivalent to that of grape seed oil and flaxseed oil. Its good antioxidant activity was related to its rich squalene, phytosterol and unsaturated fatty acid.