The IP SANs have gained widespread applications for their low deployment cost, but the performance of IP SANs is an issue that people have long been concerned about. Caching data on fast devices will improve the overall performance of an IP SAN system. This paper presents a cache system which is hosted on the iSCSI target. The system uses the DRAM memory on the iSCSI target as cache resources to provide applications with better I/O performance, which enhances the utilization rate of both CPU and DRAM resources on the iSCSI target CPU. The experimental results show that, the I/O pressure on the back-end storage system is greatly alleviated and the applications perform much better.