Beam loss monitoring (BLM) system has been commonly used to detect the vacuum leakage. The existing BLM system for Hefei Light Source (HLS) was built in 2000. It played an important role in analyzing beam loss distribution and regulating the machine operation parameters [1, 2]. Recently, HLS is being upgraded to HLS II. The emittance will be decreased to increase the brilliance of synchrotron radiation. The Touschek lifetime will be much shorter than before, and dominate the total beam lifetime. It is necessary to redesign the BLM system for HLS II. The most important part of this work is to find a better method of monitoring Touschek lifetime by BLM system while keeping its general functions. According to the results of our research, a preliminary theoretical design for the new BLM system is proposed in this paper. This new system will play an important role in the storage ring commissioning, troubleshooting, and beam lifetime studying.