A 5G wideband MIMO antenna system based on coupled loop antennas and a mobile terminal are disclosed. The antenna system comprises at least four antenna units comprising an antenna frame, a first coupling branch, a second coupling branch, a feed branch and an ground branch, wherein one end of the first coupling branch and one end of the ground branch are overlapped in the thickness or length direction of the frame, one end of the second coupling branch and one end of the feed branch are overlapped in the thickness or length direction of the frame. A traditional loop antenna is converted into a coupled loop antenna with three coupling regions. The coupled loop antenna system is high in antenna efficiency, good in isolation, simple in structure and easy to manufacture and has a small height when placed vertically, thereby making the mobile terminal lighter and thinner.