Cordyceps has long been considered as a valuable medicinal herb known to possess numerous biological activities, including anti-microbial, anti-cancer, anti-metastasis and immunomodulatory effects. With its benefits, many studies on optimizing the cultivation and production of C. militaris have been carried out. In addition, extraction methods have also been improved to intense efficiency extract the medicinal substances contained in this rare fungi. In this study, the aim was to optimize the process of C. militaris extraction from fruiting bodies based on 17 experimental data using water extraction method. The factors that affects to the extraction productivity such as: extraction temperature, extraction time and water/fungi ratio were investigated within a certain range. The experiments were arranged according to the Box-Behnken design, and then the results was optimized by Design expert software (version 13). In the optimal condition, the maximum productivity can be up to 32.23% with the extraction temperature is at 98oC, the water/fungi ratio is 18:1 and the extraction time is 4 hours.