The multicomponent mixed work medium throttling refrigerating agent applicable to medium-low temp. zone includes five groups of substances, the sum of their mole concentration is 100%, in which first group includes methane, krypton or mixture, total mole concentration is 5%-45%, second group includes tetrafluoromethane, nitrogen trifluoride or mixture, total mole concentration is 15%-55%; fourth group includes propylene, propane, perfluoropane, 1,1,1-trifluoroethane, 1,1-bifluoroethane, fluoroethane, propadiene, cyclopropane, or mixture, total mole concentration is 5%-25%; fifth group includes 1-butylene, isobutane, 2-methylbutane, 1-pentene, 3-methyl-1-butylene, 2-methylpentane, 2-butylene, isobutylene, n-butane, perfluorobutane, n-pentane or mixture, total mole concentration is 5%-25%.