A bit rate control method device obtains a bit rate control mode and coding control parameters of a current short period in a long period, determines a frame-level coding parameter of the current short period, and transmits the frame-level coding parameter to an encoder. Second bit stream information is obtained and statistical analysis is performed which includes complexity information of the current video frame, the number of the encoded bits in the current short period, and coding quality information of the current short period, so as to encode a video frame of the next, adjacent short period by calculating a frame-level coding parameter of the next, adjacent short period. By the present solution, the storage space is allocated reasonably under the condition that the image satisfies a certain quality.