  China Spallation Neutron Source(CSNS) target power will upgrade to 500
kW(CSNS-II) from 300kW, energy gain of H-Linac will up to 300 MeV from 80 MeV
using about 50 superconductor cavities. LLRF is an important device for
controlling the amplitude and phase of the SRF cavity field to be less than
0.6% and 0.6 deg. The parameters and requirements for CSNS-II Linac LLRF are
presented here. The preliminary design work and algorithm verification progress
and results at C-ADS Injector-I are introduced.
