Jerusalem artichoke (JA) is an important source of inulin, a dietary fiber with many health benefits. To investigate the potential of JA on antioxidant activity of coffee, JA coffee was made by adding roasted JA tuber to Vietnamese coffee at a ratio 1:1 (w/w). The TPC increased by 13.6% in JA-coffee affecting higher antioxidant activity by 48.0% and 26.9% in ORAC and DPPH assays, respectively. Additionally, JA improved such coffee characteristics as flavor and foam. Mass spectrometric analysis showed that the majority of inulin contents were DP 3 and DP 4. Furthermore, a food-grade microemulsion system which was composed of grape seed oil, soya lecithin, ethanol, and water was developed and applied to phenolic compounds extracted from spent coffee. Finally, the uniformity of microemulsions was improved by the LiposoFast which confirmed by Cryo-SEM.