A double-guidance shift fork transmission box, including a shift fork box body, wherein a shift fork transmission structure and two parallel guide shafts are mounted on the body; a transmission sliding block component is arranged between the guide shafts and can freely slide along them, and the component is connected to the transmission structure. For a conventional shift fork transmission structure having no or one guide shaft, the transmission sliding block component, in the motion process, is affected by thrust of the power output shaft and motion resistance of the shift fork transmission structure only, so that mechanical transmission efficacy and mechanical efficiency of the shift fork and the shift fork box are improved, and stress of the transmission sliding block component on non-axial direction of the guide shaft is eliminated; and thrust generated from the power output shaft is transmitted onto the shift fork transmission structure without loss.