Yang, L. Chen, L. He, Y. Huang, S.C. Li, C.L. Li, C.X. Li, Y.M. Lu, L. Shi, A. Sun, L.P. Wu, A.D. Zhang, S.H. JACoW Geneva, Switzerland 978-3-95450-182-3 10.18429/JACoW-IPAC2017-MOPVA082 English 1055-1057 MOPVA082 Contribution to a conference proceedings 2017 2017-05 http://dx.doi.org/10.18429/JACoW-IPAC2017-MOPVA082 http://jacow.org/ipac2017/papers/mopva082.pdf The China-Accelerator Driven Sub-critical System (C-ADS) injector II has already commissioned with a CW 1 mA and a pulsed 10 mA proton beam. The beam energy achieved 10 MeV. The superconducting linac (SCL) is routinely operating at 4.7 MV/m average accelerating gradient in the low-beta cryomodules. Field emission and surface contaminants of the SCL limit the gradient in-crease in the beam commissioning. Hence, in order to increase the SCL accelerating gradient, reduce field emis-sion and remove surface pollutants, in-situ plasma pro-cessing R&D in a 1.3 GHz single-cell SRF cavity has being studied. In this paper, the current effort of plasma processing R&D in a 1.3 GHz single-cell SRF cavity will be presented in details and the future plan will be also reported.