The invention provides a method for directly absorbing solar energy by ionic liquid solution-based nano-fluid through air conditioning and heat pump circulation as well as an apparatus thereof. The method is characterized in that a working medium solution is slowly added in phosphate imidazoles ionic liquid, the materials are mixed to obtain basic liquid, wherein, the phosphate imidazoles ionic liquid content accounts for 60-95 wt% of the working medium solution; then, the nano particles are added in the basic liquid, the materials are continuously stirred until the materials are completely mixed, and the stable phosphate imidazoles ionic liquid solution-based nano fluid is obtained, the nano particles content content accounts for 0.01-0.5 wt% of the phosphate imidazoles ionic liquid solution-based nano fluid, and the phosphate imidazoles ionic liquid solution-based nano fluid is poured to a solution storage tank of the apparatus before the apparatus operates. The apparatus has the advantages of energy saving, environmental protection, simple structure, easy miniaturization, and reliable performance.