A Digital BPM signal processor has being designed in SINAP since 2009. It is a general platform that can be used for the signal processing of a variety of BPM, like stripline BPM, cavity BPM and button BPM. After years of optimization, the DBPM has been used massively on DCLS and SXFEL. And the turn-by-turn resolution of the storage ring DBPM on SSRF is 0.34μm. This topic will introduce the development and applications of the DBPM at SINAP, also the future DBPM development for next generation light source will be discussed here. INTRODUCTION BPM is an important diagnostic instrument in accelerator. It provides the beam position in tunnel, which can be used for accurate beam control and other beam parameters measurements. There have a variety of BPM sensors for different occasions on accelerator, such as stripline BPM, button BPM, cavity BPM, shoebox BPM, et.al. Except for the sensor, the BPM signal processing electronic is a key component of the BPM system. The signal processing system can mainly including RF signal conditioning, ADCs digitizing analogue signal into digital signal, FPGA processing digital signal and calculate the beam position, data acquisition in CPU sending out the results and communicating with control center through LAN. Figure 1 is the block diagram of BPM signal processing system. Figure 1: BPM signal processing system. BPM sensors are installed at the concerned place of the accelerator, larger accelerator always containing more BPMs. For example SSRF is a 432m electron storage ring and contains about 200 BPMs, and future Shanghai Hard X-ray FEL will have more than 200 BPMs along the 3km facility. Since 2009, SSRF started the development of DBPM processor, the objective is to develop a stand-alone general hardware platform that can be used for diverse signal processing applications on accelerator. The first version DBPM completed at about 2011, and lab-tests and on-line beam tests have been carried out. The results shown that the turn-by-turn data resolution can be better than 1μm, and the 10Hz SA data can be read correctly [1]. After five years’ optimization, a second version DBPM has been designed and firstly made mass field application on DCLS and SXFEL, and small amount DBPMs is under test on SSRF. The DBPM specification is listed in Table 1. Table 1: DBPM Specifications