As the world's largest palm oil producer, Indonesia is subjected to utilize palm oil as a precursor of alkyl polyglycoside (APG) synthesis for Enhanced Oil Recovery (EOR) application. In this study, the optimization of APG C-4 synthesis as an intermediate product was conducted to maximize the APG C-12 conversion in further synthesis by referring to indirect method. Optimization of APG C-4 synthesis was carried out using reflux method by reacting glucose with 1-butanol in equivalent ratio of 1:8 and 8:1 (mole/mole), and p-toluene sulfonic acid (PTSA) 1 % (w/w) of glucose with various temperatures and reaction times. After neutralizing and evaporating the solvent, the mixture of APG C-4 then was characterized using FTIR, UV-Vis, and LC-MS, followed by evaluation of interfacial tension (IFT) using spinning drop tensiometer. The mixture of APG C-4 giving the lowest IFT value then was subjected for its ability as EOR application by using capillary pressure method with n-hexane as a crude oil analog. The mixture of APG C-4 from excess 1-butanol synthesis at 110 °C and 6 h exhibited the lowest IFT value of 0.5777 mN/m (6,000 rpm) and 0.1773 mN/m (3,000 rpm). However, the study on its ability on EOR application showed zero lifted on n-hexane recovery. This study revealed that further trans-acetalization of APG C-4 mixture should be carried out to improve its ability in EOR application.