In order to meet the requirements of miniaturization and high isolation MIMO antenna in wireless communication system, a compact UWB multiple-input multiple-output (MIMO) antenna with high isolation between units is proposed. The antenna size is only 41 mm×25 mm×1. 6 mm. The compact UWB MIMO antenna using a spanner microstrip line to widen bandwidth, Serrated grounding structure and comb-shaped electromagnetic band gap ( EBG) structure on the ground plane of the antenna helps to obtain higher isolation, introducing C-shaped branches on the antenna discards worldwide interoperability for X-Band satellite downlink communication band. The optimization of various parameters proves that the proposed UWB-MIMO antenna satisfies the port reflection coefficient S11 < -10 dB in the 3. 1~ 12. 0 GHz band, and the notch band is 7. 0 ~ 7. 9 GHz, the isolation is greater than 20 dB in the entire working bandwidth. The UWB-MIMO antenna designed in this paper has good radiation characteristics, stable gain and low envelope correlation coefficient (ECC<0. 006), which is suitable for UWB-MIMO system applications.