Abstract: The solid storage system is an important way to solve the problem of computer memory wall. But the existing block-based storage management strategy can’t use the advantages of byte-addressable characteristics in solid storage system and causes write amplification, which seriously reduces the I/O performance and lifetime of NVM devices. In term of this problem, the new solid storage system with asymmetric interface named APMSS is presented, and the management of read and write access request are separated by the analysis of two type access request. The read access request is still managed by block unit to avoid increasing the overhead of I/O stack and keep high performance by cache. The minimized direct write strategy is designed and the write access request is managed by dynamic granularity to reduce the communication and written data to solid storage system. At the same time, the multi-granularity mapping algorithm is designed to avoid exchanging amplification between memory and solid storage system and improve the I/O performance. Then the write amplification of solid storage system could be avoided and the write performance of NVM devices could be improved. The prototype is implemented based on PMBD which is the open source solid storage system simulator. Fio and Filebench are used to test the read and write performance of Ext2 on PMBD, Ext4 on PMBD and Ext4 on APMSS. The test results show that Ext4 on APMSS can improve sequential write performance by 9.6%~29.8% compared with Ext2 and Ext4 on PMBD.