A method for a multi-video stream transmission to a client terminal implemented on a computing device having at least one processor, at least one computer-readable storage medium, and a communication platform connected to a network, comprising: obtaining a multi-video stream including a plurality of video streams corresponding to a plurality of scenes captured by a plurality of cameras, each of the plurality of video streams including multiple key frames characterized by a frame rate and a key frame interval, a key frame interval of a video stream being a count of frames between two successive key frames in the video stream, wherein at least two frame rates of the plurality of video streams are different; determining, based on a plurality of frame rates and a plurality of key frame intervals of the plurality of video streams, a delay time of an initial key frame for each of the plurality of video streams; processing, based on the delay time of the initial key frame in each of the plurality of video streams, the plurality of video streams to determine a desired sending time of the initial key frame in the corresponding video streams, the desired sending time of the initial key frame in a video stream corresponding to a time when the initial key frame of the video stream is sent to the client terminal; and transmitting, to the client terminal, the plurality of processed video streams, wherein determining a delay time of an initial key frame for each of the plurality of video streams comprises: normalizing, based on the plurality of frame rates and the plurality of key frame intervals, the plurality of key frame intervals to generate a plurality of normalized key frame intervals; and determining, based on the plurality of normalized key frame intervals, the delay time of the initial key frame for each of the plurality of video streams. obtaining a multi-video stream including a plurality of video streams corresponding to a plurality of scenes captured by a plurality of cameras, each of the plurality of video streams including multiple key frames characterized by a frame rate and a key frame interval, a key frame interval of a video stream being a count of frames between two successive key frames in the video stream, wherein at least two frame rates of the plurality of video streams are different; determining, based on a plurality of frame rates and a plurality of key frame intervals of the plurality of video streams, a delay time of an initial key frame for each of the plurality of video streams; processing, based on the delay time of the initial key frame in each of the plurality of video streams, the plurality of video streams to determine a desired sending time of the initial key frame in the corresponding video streams, the desired sending time of the initial key frame in a video stream corresponding to a time when the initial key frame of the video stream is sent to the client terminal; and transmitting, to the client terminal, the plurality of processed video streams, wherein determining a delay time of an initial key frame for each of the plurality of video streams comprises: normalizing, based on the plurality of frame rates and the plurality of key frame intervals, the plurality of key frame intervals to generate a plurality of normalized key frame intervals; and determining, based on the plurality of normalized key frame intervals, the delay time of the initial key frame for each of the plurality of video streams. normalizing, based on the plurality of frame rates and the plurality of key frame intervals, the plurality of key frame intervals to generate a plurality of normalized key frame intervals; and determining, based on the plurality of normalized key frame intervals, the delay time of the initial key frame for each of the plurality of video streams.