During the Phase Ⅱ project of NSRL, a turn by turn BPM (Beam Position Monitor) system is proposedfor storage ring diagnostics which engages log-ratio electronics circuit to measure machine properties of the HLS(Hefei Light Source) storage ring. The log-ratio processor works at 408 MHz, twice the RF frequency of HLS. Mod-ern logarithmic amplifiers with wide dynamic range, great bandwidth, good logarithmic conformance, and low costare attractive for beam position measurements. Injection kicker and the stripline-electrode resonant exciting methodsare used to excite beam for nonlinear beam dynamics and phase space studies of stored beam. Up to 2 seconds of dataacquisition is ensured. In this paper we present the performance of each component and preliminary test results of theturn-by-turn BPM system.