Abstract: A kind of novel flame-retardant is separated from polypropylene through solvent picking-up. The structure of this compound I is confirmed by FTIR, GC/MS, element analysis, 1H NMR and 13C NMR, and so on. Several methods are proofed with one another. This compound I is tetrabromobisphends-bis (2, 3-dibromopropyl) ether, which provides a useful reference to resolution of complicated unknown compounds.