The invention relates the multicomponent mixed working substance used for preparing dual-temperature by single-machine vapor compression refrigerator. The low temperature is between -60- -40Deg.C and the high temperature is between -25- 10Deg.C. The multicomponent mixed working substance comprises lower boiling working substance and high boiling working substance. The lower boiling working substance comprises tetrafluoromethane, ethylene, ethane, fluoroethylene, trifluoromethane, fluoromethane, hydrofluoeic ether, carbon dioxide, difluoromethane and penfluoroethane; the high boiling working substance comprises trifluoro-thane, hydrofluoeic ether, propylene, propane, perfluoropropylamine, propadiene, cyclopropane, difluo-monochloromethane, penta-monochloroethane, perfluoroethane, difluoroethane, isobutene, butane, butylenes, isobutylene, sevofluoropropane, hexafluoropropane, penfluoropropane and tetrachloromonofluoroethane.