According to the requirements of wireless communication equipment for MIMO antennas with multi-band,simple structure and high isolation, a new dual-band broadband eight-element multiple input multiple output (MIMO) antenna for 5G mobile phones is proposed. The antenna substrate was made of FR4 and the overall size was 150 mm x75 mmx 0.4 mm. The “U-shaped” radiating element of the antenna was loaded on one side of FR4, and the size was only 10 mm x 3.6 mm. Each element was divided into two parts by the feed source, producing two resonant modes of 3.5 GHz and 4.9 GHz,respectively. At the same time, on one side of the metal plate, the effective paths of the current were changed and the current transmission between elements was blocked by etching the rectangular slots, so as to increase the working frequency bandwidth and weaken the coupling degree between elements. Simulation and measured results showed that when S11 was less than -6dB, the antenna could cover 3.3 GHz-3.6 GHz and 4.8 GHz-5.1 GHz. The isolation among antenna elements was better than 13.6 dB,and the radiation efficiency was above 67%. Compared with the traditional antennas,this antenna has advantages in structure, bandwidth and isolation, and has a good application prospect.