In order to clarify the changes of digestion and metabolism of main nutrients (protein and oil) in walnut and their antioxidant properties， this study took Juglans regia 'Xinxin 2' as the research object， and analyzed the metabolic processes of the two main components of protein and oil by using a simulated gastrointestinal digestive model. The metabolic changes at five different stages during digestion were determined by GC-MS and HPLC-MS/MS. The results showed that the total amount of free amino acids in protein digestion products increased from 3.50 μg/g to 61.85 μg/g with the passage of gastrointestinal digestion time (P<0.05)， For example， the content of arginine increased from 0.24 μg/g to 25.50 μg/g， and the content of lysine increased from 0.12 μg/g to 6.03 μg/g. The content of free fatty acids increased from 1.08 mg/g to 413.20 mg/g (P<0.05)， indicating that new fatty acids such as cis-11-eicosanoenoic acid and trans-10-19-enoenoic acid were produced under the action of enzymes during digestion. To explore the antioxidant properties of 5 different matching groups (the mass ratio of protein to oil was 1∶0， 7∶3， 1∶1， 3∶7， 0∶1) after digestion. The results showed that the antioxidant capacity increased with the increase of substance concentration. It was found that the antioxidant capacity was strongest when the protein-oil mass ratio was 1∶0， and when the concentration was 50 mg/mL， the DPPH and ABTS+ clearance rates were 80.65% and 81.02%， respectively. The absorbance value of Fe3+ reducing power was 1.55， indicating that the antioxidant capacity of walnut protein was better than that of oil， because the two digestive products of protein had antioxidant properties. This study provides data support for clarifying the digestion and metabolism mechanism of walnut principal components， and provides reference for the development of walnut products with high antioxidant function.