Abstract: In response to the application requirements of low voltage, high isolation and low insertion loss required by the RF circuit system, by exploring the influence of the positive pair area of the switch on the driving voltage, a three-support H-type RF MEMS switch applied in X-band was designed. The switch is supported by six beams to reduce the opening voltage of the switch by increasing the area of the upper plate. The RF performance and mechanical properties of the switch were simulated by HFSS and COMSOL, respectively. After the switch was finally optimized, the insertion loss was 0.26−0.57 dB, and the isolation was greater than 31.30 dB within 8−12 GHz. The optimal value is achieved at 10.1 GHz with an insertion loss of 0.40 dB and an isolation of 50.25 dB. The switching voltage is 11V, and the switching response time is 14 μs. The switch can be combined with RF reconfigurable devices and applied to the new generation RF microwave field.