A multicast access method, characterised in that the method comprises: determining whether a current received frame sent by a multicast server can be independently decoded; when the current received frame cannot be independently decoded, backing up the current received frame; calculating a time interval T1 between the current received frame and a previous frame sent by the multicast server that can be independently decoded; estimating a time delay T2 for re-coding the current received frame into a frame that can be independently decoded; and calculating a number N of frames that cannot be independently decoded between the current received frame and a next frame sent by the multicast server that can be independently decoded; determining whether T1 is smaller than or equal to T2*N; when T1 is smaller than or equal to T2*N, selecting, according to a multicast group quick access request from a terminal, the previous frame sent by the multicast server that can be independently decoded as a frame to be played first, generating a playing strategy, sending the selected frame that can be independently decoded for first playing and the playing strategy to the terminal and sending a subsequent received frame that cannot be independently decoded to the terminal; when T1 is greater than T2*N, re-coding the current received frame into a frame that can be independently decoded, selecting, according to a multicast group quick access request from a terminal, the re-coded current frame as a frame to be played first, re-coding a subsequent frame sent by the multicast server that cannot be independently decoded between the selected frame to be played first and the next frame sent by the multicast server that can be independently decoded into a frame that can be independently decoded, generating a playing strategy, and sending the selected frame that can be independently decoded for first playing and the playing strategy to the terminal, and sending the subsequent re-coded frame that can be independently decoded to the terminal, wherein the playing strategy comprises a playing start time of the selected frame for first playing that can be independently decoded, and the total playing time of the selected frame for first playing that can be independently decoded and the subsequent frame. determining whether a current received frame sent by a multicast server can be independently decoded; when the current received frame cannot be independently decoded, backing up the current received frame; calculating a time interval T1 between the current received frame and a previous frame sent by the multicast server that can be independently decoded; estimating a time delay T2 for re-coding the current received frame into a frame that can be independently decoded; and calculating a number N of frames that cannot be independently decoded between the current received frame and a next frame sent by the multicast server that can be independently decoded; determining whether T1 is smaller than or equal to T2*N; when T1 is smaller than or equal to T2*N, selecting, according to a multicast group quick access request from a terminal, the previous frame sent by the multicast server that can be independently decoded as a frame to be played first, generating a playing strategy, sending the selected frame that can be independently decoded for first playing and the playing strategy to the terminal and sending a subsequent received frame that cannot be independently decoded to the terminal; when T1 is greater than T2*N, re-coding the current received frame into a frame that can be independently decoded, selecting, according to a multicast group quick access request from a terminal, the re-coded current frame as a frame to be played first, re-coding a subsequent frame sent by the multicast server that cannot be independently decoded between the selected frame to be played first and the next frame sent by the multicast server that can be independently decoded into a frame that can be independently decoded, generating a playing strategy, and sending the selected frame that can be independently decoded for first playing and the playing strategy to the terminal, and sending the subsequent re-coded frame that can be independently decoded to the terminal, wherein the playing strategy comprises a playing start time of the selected frame for first playing that can be independently decoded, and the total playing time of the selected frame for first playing that can be independently decoded and the subsequent frame.