The invention relates to a simulation experiment device aiming at a building exterior wall fireproof structure and the performance of the fireproof structure, and aims at solving the defect of absence of the simulation experiment device aiming at the building exterior wall fireproof structure in the prior art. A left bracket and a right bracket are respectively located at two sides of a window and horizontally correspond to each other, wherein horizontal baffle plates are arranged on the left bracket and the right bracket; a left vertical baffle plate is arranged at the left sides, located on a simulative main wall, of the horizontal baffle plates, and is in rotational fit with the simulative main wall; and a right vertical baffle plate is arranged on the right sides, located on the simulative main wall, of the horizontal baffle plates, and is in the rotational fit with the simulative main wall. The simulation experiment device is capable of achieving research on fireproof performances and influencing mechanisms of the building exterior wall fireproof structure such as the horizontal baffle plate, the vertical baffle plate and a fire-barrier belt, and is also capable of researching the fireproof performance of a building exterior wall heat-preservation material and researching the fireproof performance in the conditions of multiple complicated building exterior wall fireproof structures.