The present invention discloses a mangosteen pericarp extract and process for its preparation thereof. The mangosteen pericarp extract containing α-mangostin and γ-mangostin which obtains from preparation steps comprising fragmentation, organic solvent soaking, aqueous solution, or acidic solution soaking, concentration, spray drying and grinding steps from the rind of the mangosteen. The present invention has advantages of simple preparation process to address efficiency issue, no need to have heating under reflux in extraction steps and the solvents which used are friendly to human body and environment.