Spoke cavities have been developed and have apparent advantages for high current proton accelerator based on Fig.1(color online)The electromagnetic field distribution.superconductivity at low and medium energy region.As the research and the technical reserve,Institute of Modern Physics(IMP)has started the R&D program of a double spoke cavity(operating frequency 325 MHz,0=0.52),within the framework of China Accelerator Driven System(C-ADS)project.The RF design and mechanical structure design have been finished,and two prototype cavities were manufactured in Harbin.