Curcuma domestica is one of traditional medicinal plants that is found in Gunungpati Semarang. However the dried product do not achieve optimal standard quality for simplicia in terms of microbial contaminant and in an industrial scale household. Knowledge on how to use sterilization to produce better simplicia and reducing contaminant has not been known by farmers, yet. The purpose of this activity was to obtain the best heating treatment on sterilization of Curcuma simplicia using several temperature under sunlight and oven device. It was also want to show microbial growth after heating at several times and their influence on the quality of simplicia after treatment. The method was conducted by simplicia sterilization of C. domestica using sunlight sterilization for a week and using oven at a temperature of 30 0 C, 40 0 C, 50 0 C and 60 0 C for 1, 3, 6, 9, 12, 24, and 48 hours. The results showed that heating at temperature of 50 0 C for 48 hours obtained the best simplicia, followed by heating at a temperature of 60 0 C for 16-48 hours without contaminants after storing period for 3 months.