Abstract: A hierarchical shared secondary storage (L2-Cache) structure for a heterogeneous multi-core SoC face to high density calculation is proposed in this paper to ease the speed difference between data processing and data storage. The hierarchical storage structure provides object data caching function and reduce the pollution of secondary storage using count replacement strategy to improve valid data hit rate. The structure can also increase the effective memory bandwidth by L2-main memory synchronous operation and accurate prefetching in data computing interval time. Final test results show that, L2-Cache design can adapt for various data's feature of different applications.The new design increase the average fetch performance of about 31.1%, and gain 1.573 speed ratio highest of different sizes of matrix, and reduce the average computing time of about 27.8%.