By using PEG 1500 glass chromatog raphy column, 9 kinds of bactericidal substances (m-hydroxybenzoic acid,
methyl salicylate , catechol, ace tic acid, ace taldehyde, acrylic acid, diethy l sulphide , bo rneol -2 and camphanone-2)and 9 kinds of aromatic substances(ethyl acetoace tate , allyl alco hol , citral , acety lmethy lcarbinol , iso-pentanol, borneol -2 , ethyl acetate , benzaldehyde and terpineol) were ex tracted out throug h the separation experiments on the volatile gas released from 12 main g reenery tree species in Shanghai.Furthermo re , the hygienical substances ing redient proportion betw een the different trees was measured.T his experiment provides scientific basis for co nstructing healthy ecological g reenland .