In this paper, a compact triple-notch ultra-wideband multiple-input multiple ( UWB-MIMO) antenna is proposed, which combines a semicircle and a regular hexagon as a radiating patch, and a grounding plate is introduced into the belt. “Comb” slot-like Tshaped branches to achieve higher isolation, the antenna size is 36 mm×18 mm×1. 6 mm. WiMAX (3. 3~ 3. 6 GHz) and WLAN parts are realized by etching the inverted “ Ω”-shaped groove on the radiation patch, etching the “ U”-shaped groove on the feeder and introducing the “U”-shaped branch next to the patch. Frequency band (5. 725~ 5. 825 GHz) and X-band downlink frequency (7. 25~ 7. 75 GHz) are notched in three frequency bands. Both simulation and actual measurement results show that the working bandwidth of the UWB-MIMO antenna is 1. 9 ~ 10. 6 GHz, the relative bandwidth reaches 139%, and the three notch frequency bands are 2. 9 ~ 3. 7 GHz, 5. 6~ 6. 0 GHz and 7. 05~ 7. 76 GHz, the degree of isolation is greater than 20 dB, and the envelope correlation coefficient ECC is less than 0. 003, indicating that the antenna has good characteristics in all aspects and can meet the requirements of UWB-MIMO antennas.