Purple sweet potato (Ipomoea batatas L. Lam) contains quite much antioxidant, especially anthocyanin. Antioxidant stability can be affected by some factors such as the existence of oxygen, light, pH, dan temperature. The aim of this research is to study the effect of pH and temperature towards antioxidant activity using response surface methodology. Antioxidant from purple sweet potato was extracted by maceration process and then the solutions were vaporized using rotary evaporator. The antioxidant was extracted using combination of ethanol and ethyl acetate solution (ratio 100:0, 80:20, 60:40, 40:60, 80:20, 0:100) at random temperature (room temperature, 40 C, and 60 C) and time (3, 6, and 9 hours) to optimized the extraction. Next, the best extract with the highest antioxidant activity was given pH (pH 4-8) and temperature treatment (65 C, 75 C, 85 C, and 100 C). The pH and temperature treatment were given in order to test the antioxidant activity (DPPH method) also the total phenolic. The result then was processed by response surface methodology program to analyze the optimum pH and temperature in resulting the highest antioxidant activity also total phenolic. The result was that the antioxidant extract treated by pH 3,77 and temperature 56,94 C has a higher antioxidant activity and total phenolic than the other pH and temperature that treated.