In this paper, a UWB-MIMO antenna based on decoupling of EBG and ground branches is designed. The design uses a conical feed line to feed a slotted elliptical monopole antenna, achieving an impedance bandwidth of 3.8GHz to 12.4GHz (relative bandwidth of 106%). At the same time, a defect ground structure and T-shaped, H-shaped ground branches are used for decoupling, resulting in an isolation degree of less than -20dB between the four feeding ports within the antenna operating frequency band. In addition, The antenna also has stable radiation direction and excellent gain performance.