Abstract: For the CP reflectarray忆s problem of narrow bandwith, this paper combines the resonant characteristic of the microstrip antenna and linearly polarized reflectarray忆s idea of improving the bandwith, we present a new multi-resonant “ ring shaped broadband CP reflectarray element, the unit忆s broadband CP principle is analyzed by the current distribution of the element. A 169-element CP reflectarray using element rotation technique has been designed and measured: 3dB axial ra tio bandwith is over 41%(8. 1GHz-12. 2GHz), The best efficiency of 59. 94% and the gain of 24. 91 dB occur at 9. 9 GHz. Measured results are agreed with the simulation results, We get broadband CP and high efficiency.