One of plants fruit that has potency as drug is mangosteen (Garcinia mangostana L.), especially on part skin the fruit. Main Bioactive compound and be major compound and have various bioactivity in skin fruit mangosteen is α- mangostin. This research has succesfull isolate α- mangostin through maceration process, chromatography column and recrystallization. Isolation procedure in this research is modification from research before . α- mangostin is produced from isolation procedure in this research is higher than research before. Isolates obtained from purification process is 0, 4 gram of a 100 gram sample. Next group function in structure of α- mangostin identified use IR spectroscopy.