The floor air outlet is so designed to achieve reasonable air distribution of bottom admission and top expulsion. The outlet box is provided with a static pressure box, which allows a lower air velocity and lower noise at floor air outlet. The design of the mosquito screen effectively prevents foreign objects from entering into the vent tube. It is allowed to change the depth of outlet box based on site conditions so as to adapt it to the demands of different customers. Instead of traditional metallic material, personal injury can be avoided by using wear-resistant soft material.