The invention discloses an environment wind field simulation unit and an environment wind field simulation system applied to fireproof performance test of a building exterior wall. The unit comprises a shell, and a transmission fan, electric air valves, a rectifying grating and an air supply duct which are sequentially distributed in the shell, wherein the transmission fan at least corresponds to the three electric air valves, the quantities of the rectifying grating and the air supply duct are equal to that of the electric air valves in a one-to-one correspondence manner, and a spherical nozzle is arranged on the tai lend of each air supply duct. The system comprises a plurality of environment wind field simulation units, a support and universal wheels for supporting and moving the units, and a control system used for controlling the air supply speed and direction of the system. Through the reasonable structural design, not only can the environment wind fields at different heights of the whole building exterior wall can be simulated in a reduced-scale manner, but also the environment wind field outside the firing layer can be simulated on a full-scale manner, thus providing basis and guarantee for accurately conducting the fireproof performance test of high-rise or ultrahigh-rise buildings.