The invention discloses an environment-friendly smoke exhaust device based on building fire protection, and relates to the technical field of building fire protection. The device comprises a shell andan air guide window, wherein a supporting plate is fixedly connected to the inner wall of the lower end of the interior of the shell; a mounting groove is formed at the position, above the supportingplate, of a front side plate of the shell, and meanwhile, an exhaust pipe is connected to the position, above the supporting plate, of a rear side plate of the shell in a communicating manner; the outer wall of the exhaust pipe is fixedly sleeved with a solar cell panel; the air guide window is fixedly arranged in the mounting groove; and the air guide window comprises a plurality of air guide plates, connecting plates and a linkage plate, and the air guide plates are arranged in parallel in the vertical direction. Through arrangement of the series of structures and the cooperation of the structures, the device can rapidly exhaust smoke in a building in a large range in use, meanwhile, the device is provided with the independent power supply system, so that the working stability is high,in addition, the device can also carry out cooling fire-extinguishing protection, so that a very good role in protecting the device is achieved, and the normal use is guaranteed.