Chen, J. Lai, L.W. Leng, Y.B. Yan, Y.B. Yu, L.Y. Yuan, R.X. JACoW Geneva, Switzerland 978-3-95450-177-9 10.18429/JACoW-IBIC2016-WEPG18 English 662-665 WEPG18 cavity FEL electron pick-up undulator Contribution to a conference proceedings 2017 2017-02 http://dx.doi.org/10.18429/JACoW-IBIC2016-WEPG18 http://jacow.org/ibic2016/papers/wepg18.pdf Dalian Coherent Light Source (DCLS) is a new FEL fa-cility under construction in China. Cavity beam position monitor (CBPM) is employed to measure the transverse position with a micron level resolution requirement in the undulator section. The design of cavity, RF front end and data acquisition (DAQ) system will be introduced in this paper. The preliminary measurement result with beam at Shanghai Deep ultraviolet (SDUV) FEL facility will be addressed as well.