Abstract: In order to prepare the potassium hydroxycitrate from the fruits of Garcinia cambogia L.,the water extraction method was adopted to extract hydroxycitric acid from the powders prepared from G. cambogia L. fruits. The extractions were identified by the chromogenic reaction with ammonium monovanadate,thin layer chromatographic analysis and the HPLC analysis. The extraction process was optimized by the single factor test and the orthogonal test. The optimal conditions were as follows:The solid liquid ratio was 1:18,the condensive fold was 5,the alcohol degree was 60%vol,and the pH value was 12. The effects of various factors on the recovery rate of free hydroxycitric acid were in the order of solid liquid ratio>condensive fold>pH>alcohol degree. Under these optimal conditions,the recovery rate of potassium hydroxycitrate from the fruits of G. cambogia L. was 3.24%±0.32%. In the extraction process,KOH was used to protect the free hydroxycitric acid under the alkaline condition to form the potassium hydroxycitrate. A single peak whose retention time was the same to that of the hydroxycitric acid was detected by HPLC and its purity was 52.10%±0.53%. This method was better than the existing technology.