A plum tree extract comprises 0.5-50 wt% squalene The plum tree extract mainly comes from fat-soluble portion and/or water-soluble portion of non-fruit part of plum tree A method for preparing the plum tree extract, comprises using supercritical carbon dioxide or non-polar organic solvent to extract to obtain fat-soluble portion, and using alcohol-water solution to extract the residue to obtain water-soluble portion A medicine composition comprising the plum tree extract, and use thereof.