The utility model provides a filter screen fixing device of a fresh air device, which is characterized in that a shell of the fresh air device is provided with a mounting port, the fixing device is detachably arranged inside the fresh air device through the mounting port, and the fixing device comprises a supporting plate, a filter screen and a filter screen fixing plate, wherein the supporting plate passes through the mounting port and is perpendicular to the plane of the mounting port; the buckle plate is perpendicularly connected with the supporting plate, one end of the buckle plate is fixedly connected with the outer end of the supporting plate, and the shape of the buckle plate is matched with that of the mounting opening; the handle is arranged on the outer side of the buckle plate,and the handle is sunken towards the supporting plate to be arc-shaped; wherein the filter screen is arranged on the supporting plate and is arranged in the mounting opening. According to the filterscreen fixing device of the fresh air device, after the fresh air device operates for a long time, a large amount of dust is accumulated on the filter screen, the filter screen is detachably fixed inthe fresh air device through the fixing device, a user can conveniently detach the filter screen, and then the failed filter screen is replaced.