A frequency reconfigurable multiple input multiple output (MIMO) antenna based on a novel coplanar waveguide (CPW) is designed in this work. The switching elements are used in the antenna to achieve the discrete frequency tunability of discrete frequencies of 6.17-9.38 GHz and 19.53-25.48 GHz by controlling the switch to change the current length of the CPW. The conversion mode does not require additional matching circuits, resulting in a more compact structure. The antenna unit is CPW-fed and etched on the dielectric substrate of F4B, and the MIMO configuration can achieve good isolation without additional decoupling devices. The simulation and test results show that both the single antenna and the MIMO antenna can realize the frequency reconfiguration characteristics. Tthe isolation between antenna units is <-20 dB, the correlation envelope coefficient is <0.05, and the diversity gain is close to 10 dB, which meets the design requirements.