The invention discloses a method and a device for acquiring cool air and an electric energy by utilizing a low-temperature medium. The low-temperature medium is used as a refrigerating agent to release condensation heat to a heat exchanging medium by means of condensation, the heat exchanging medium absorbs the condensation heat and also absorbs a collected low-grade heat energy, the refrigerating agent is condensed into liquid and then is evaporated after being decompressed, the refrigerating agent absorbs the heat of the heat exchanging medium when in evaporation to be expanded to work mechanically outwards so as to generate a mechanical energy, the refrigerating agent after working mechanically is compressed at a steam state and condensed, thereby realizing an energy conversion process of the refrigerating agent in a set of refrigerating circulation path, and circulating the process. The method and device can collect low-grade heat energy such as industrial waste heat, solar energy, air conditioner waste heat and the like and can high efficiently convert the low-grade heat energy without needing any petrochemical and mineral energies, thereby realizing zero emission, energy conservation and environmental protection and having an epoch-making significance on developing a technology comprehensively utilizing renewable energies such as industrial waste heat, reducing emission, high efficiently utilizing solar energy, air conditioner waste heat and the like.