1. A configuration information cache management system based on pre-decoding analysis, comprising a stream media processor module, a configuration information prefetching FIFO module, a configuration information memory unit, and a cache controller module; the stream media processor module is configured to parse the macro blocks in the code stream obtained from the external memory, generate a configuration information index corresponding to the subtask required for processing the macro blocks, and output the configuration information index to the configuration information prefetching FIFO module; the configuration information index comprises the address of configuration information in the external memory and the ID of the reconfigurable array that uses the configuration information; the configuration information prefetching FIFO module is configured to sequentially store the configuration information indexes generated by the stream media processor module, and provide a basis for replacement of the configuration information in the configuration information memory unit; the configuration information memory unit is configured to cache the configuration information fetched from the external memory; the cache controller module is configured to fetch a configuration information index from the configuration information prefetching FIFO module, and judge whether the required configuration information exists in the configuration information memory unit according to the address of the configuration information in the external memory; if the required configuration information exists in the configuration information memory unit, the cache controller module will directly read the configuration information; if the required configuration information does not exist in the configuration information memory unit, the cache controller module will fetch the required configuration information from the external memory, and then cache the required configuration information in the configuration information memory unit, and finally send the required configuration information to the corresponding reconfigurable array.