The design and fabrication processes of a DC-contact shunt RF MEMS switch were studied to improve its performance.A low stress electroplated Au membrane was taken as an upper electrode to implement the Au-Au direct contact.BorofloatTM glass was used as a substrate and a inside resistance was used to isolate the crosstalk between radio-frequency signal and bias voltage.Then,the distance between Au membrane and Coplanar Waveguide(CPW) was optimized to lower the insertion losses of the switch.Experimental results show that the contact resistance is 0.1 Ω under the pull-down voltage of 60 V.The insertion losses are -0.03 dB@1GH,-0.13 dB@10 GHz,-0.19 dB@20 GHz in the frequency ranges from DC to 30 GHz,which is less than -0.5 dB;the isolations are -47dB@1 GHz,-30 dB@10 GHz and -25 dB@20 GHz in the same frequency ranges,which is all better than -23 dB.The measurement results show that the fabricated RF MEMS switch is suitable for the applications of frequency ranges from DC to 30 GHz.