The utility model provides an outdoor air transmitter protection box. The protection box is composed of a box body, an upper cover, a window frame, glass, a transmitter base, a liner plate and bolts. The upper cover is fixed on the box body through the bolt. An observation opening is formed in the front surface plate of the box body. The window frame is fixed on the observation opening through the bolt. The glass is inlaid in the window frame. A fixed bolt hole is arranged at the upper part of the rear surface plate of the box body. The transmitter base is arranged on the inner bottom plate of the box body. A sealing rubber strip is fixed above the transmitter base through bolts. A sensor upper part installation hole is formed in the middle of the transmitter base. A sensor lower part insertion hole is formed in the middle of the bottom plate. A wire outlet is arranged at the lower part of the right panel of the box body. The outdoor air transmitter protection box is simple in structure, is small in size, is convenient to install, is transparent and visual, is convenient for maintenance, has good sealing performances, can prevent rainwater and air from entrance and erosion effectively, and prolongs the service life of the air transmitter in the box.