The embodiment of the invention discloses multichannel decoder-coder operation method and device. The multichannel decoder-coder operation method comprises the following steps of: dividing an encoding and decoding algorithm code into a plurality of code segments in advance; setting the corresponding relation of the code segments and channels; when a plurality of encoding and decoding algorithms need to be operated, sequentially moving the corresponding code segments of the encoding and decoding algorithms to an on-chip first program operation space from an off-chip storage space; and sequentially executing the code segments moved from the off-chip storage space for the corresponding channel. The embodiment of the invention can realize the dynamic loading of the algorithm code segments, does not need to restore a DSP (Digital Signal Processor), saves code loading operation time, and reduces system time delay.