Dolsan leaf mustard has various biological functions, including those in the immune system and cancer prevention. It contains high amounts of nutritional and medicinal compounds, which are important for maintaining optimum health. The objective of this study was to determine the total phenolics contents and antioxidant activity in Dolsan leaf mustard pickle (DLMP) during storage. DLMP methanol extracts had the highest total polyphenol and flavonoid contents of 35.56±0.01 GAE mg/g and 4.54±0.03 QE mg/g, respectively. The DPPH and ABTS radical scavenging activities in the DLMP methanol extracts showed the highest activities of 79.4 and 85.36%, respectively. The ferric reducing antioxidant power (FRAP) assay showed 2.24-3.82 mM FeSO4 eq. (p<0.05) in DLMP extracts. Overall, storage at day 14 showed the highest antioxidant activity.