Methyl Ester Sulfonate had been prepared From Ketapang Seed Oil and was used as Surfactant. The optimum condition obtained by conducting preparation in various reaction time (3.5; 4.0; 4.5; 5.0; 5.5 hours). The methyl ester was analysis by GC-MS and sulfonate group was identified by using FTIR spectroscopy. GC-MS result showed the ester consisted of methyl palmitoleic, methyl linoleic, methyl palmitate, methyl stearate, methyl oleic, methyl palmitolenat and methyl eicosenoate. The optimum condition of methyl ester sulfonate achieved at reaction time 4.5 hours provided mass of methyl ester sulfonate obtained 34.85 g. FTIR spectra of sulfonate group indicated by shifting of wave number at 1118.71cm-1 to 1029.1 cm-1. The methyl ester sulfonate has emulsion stability 71.684%, density 0.8714 g/mL, surface tension 36.232 dyne/cm 2 , and maximum absorbance 1.428 at 660 nm wavelength.