Coplanar waveguides on silicon substrate were simulated. Using MEMS (micro-electro-mechanical system) technology, the V-shaped and W-shaped groove coplanar waveguides were implemented on silicon substrate, and its characteristic impedance was 30Ω, 50Ω, 75Ω and 100Ω respectively. In addition, the characteristic impedance of coplanar waveguide (CPW) was analyzed, and the conclusion was used to guide the design of MEMS CPW. According to the measurement results, insertion loss of coplanar waveguides was below 1dB/mm. If it is fabricated with lower resistivity metal, the insertion loss will be decreased.