The paper was to explore the law of growth of A. flavus and production of aflatoxins(AFB1, AFB2, AFG1and AFG2)in raw Areca catechu and to study the optimal storage conditions of Areca catechu. Two environmental factors including temperature(temp, 20~40 ℃)and humidity(Hum, 80%~95%)were investigated on the impact of the production of aflatoxins by A. flavus in medicinal herbs. The change of moisture content and the content of total aflatoxins after storage was tested through response surface analysis(RSA)combined with Central composite design, in order to analyze the environmental condition of the least aflatoxins production. The results showed that the moisture content of Areca catechu was significantly enhanced after storage. When the humidity was in range of 90%~95% and temperature was higher than 25 ℃, A. flavus grew quickly and produced large amounts of aflatoxins on Areca catechu. The study showed that Areca catechu was not easy to mildew and produce toxins in environment with humidity less than 90%, temperature below 25 ℃. The result provided reference for establishing the optimal storage condition and for minimizing the possibility of aflatoxins contamination.