Abstract: In order to carry out the theoretical research and quantitative analysis of block cipher parallel processing, a block cipher parallel processing model based on Amdahl's law was established. Introducing data level parallelism in block, instruction level parallelism in block, data level parallelism among blocks and instruction level parallelism among blocks, a multiple dimension parallel processing model was developed to study the effects of algorithm parameters and parallelism parameters on cipher processing performance. The results show that, the algorithms with large parallel ratio possess a larger performance improvement space, and the development of any parallelism can improve the performance. But resource allocation and parallelism development should be carried on according to the algorithm structure and work modes for the specific application scenarios. This model can be taken as the guidance for the parallel processing architecture design, resource allocation and parallelism development of block cipher.