Yellow turmeric (Curcuma domestica Val.) and “white turmeric” (Kaempferia rotunda L.) has been reported contain antioxidant compound that can scavenge free radicals. The objective of the research is to observe the stability of antioxidant activity in turmeric and “white turmeric” based on pH (3-9). The best type of turmeric and pH treatment based on the antioxidant activity and total phenolic compound were chosen for examine the stability of antioxidant activity from pH and heating time (0-30 minutes). Soxhlet method with ethanol solvent is used as the extraction method for this research. The result showed that yellow turmeric with pH 3 treatments has the best antioxidant activity (IC50=67.3952±0.5068 µg/ml) and total phenolic (37.3576±2.9141 mg GAE/g sample). The antioxidant activity of yellow turmeric also unstable from pH and heating time which the best treatment is pH 3 without heating, because the longer time of heating would decrease the activity of antioxidant and total phenolic.