A video bit-stream gamma characteristic correction method and a multipoint control unit in video communication field resolve the gamma distortion problem of video image in the existing multimedia communication. In the method, the receiving end carries out correction once through carrying the gamma characteristic parameter of the transmission end in the video bit-stream; or the multipoint control unit and the receiving end correct gamma distortion of the video image in multiple steps. A multipoint processor (200) of the multipoint control unit includes a gamma characteristic parameter storing module (201), which stores gamma characteristic parameter of the video image transmission end; and a gamma characteristic correction module (202), which is connected to the gamma characteristic parameter storing module and corrects the gamma characteristic of the video image according to the gamma characteristic parameter of the video image transmission end.