The invention relates to a hot water system based on solar energy and building integration. A condenser and a plane mirror array are arranged on wall bodies constructed around a high-rise building needing a hot water system, a sunlight tracking device acquires solar energy, the solar energy is focused onto a solar energy receiver through the condenser, the solar energy receiver is a vertical cavity type heat collector, tap water is sent into the solar energy receiver by a water supply part, and through heat exchange, the solar energy receiver outputs evaporated steam which is sent to a water storage part through a heat preservation pipeline. A unique design that the solar energy and the building are integrated is adopted, and hot water supply and high-temperature distillation disinfection of domestic water of the whole building are realized, so the domestic water is more convenient and healthy, and the solar energy is utilized for heating, a pressurization water pump is replaced, electric energy is saved in the aspects of water supply and heating, the hot water system can realize single system supply of hot water for the whole building, hot water resources are effectively integrated, and the reasonable utilization of the resources is realized.