The invention relates to a half-module pivoted window mechanism applied to a sub transonic speed wind tunnel. The half-module pivoted window mechanism comprises a driving transmission module, a feedback and measurement module and a rotating module, wherein the driving transmission module consists of a support seat, a large cylindrical straight gear, an alternating current servo motor, a speed reducer, a gear press cover, a small cylindrical straight gear, a compression cover and a compression screw, the feedback and measurement module consists of a potentiometer support seat, a potentiometer, a press sheet, a shaft coupler, a small shaft and a connecting cover, and the rotating module consists of a right bearing cover, a bearing seat, a pair of precise conical roller bearings, a left bearing cover and a main shaft. Through the adoption of a cylindrical straight gear group, the half-module pivoted window mechanism can realize the movement for positive 360 degrees and negative 360 degrees, in addition, the integral hosting of the mechanism can be realized, a measurement part adopting the potentiometer as the core is adopted for the transmission matching of the cylindrical straight gear group, and the attack angle control precision being +/-3' can be realized.