Abstract: A compact UWB multiple-input multi-output antenna with band-reject is proposed in this paper. Printed on an FR4 substrate, the antenna consists of two identical antenna units placed orthogonally, and its size is 46 mm×46 mm×0.8 mm. The unit is composed of a stepped rectangle and is fed by a microstrip line. A square split ring resonant is etched on the unit to implement a band-reject function, and the electromagnetic interference of the WLAN (5.15-5.85 GHz) is suppressed. With the isolation branch at the symmetry axis of the ground plane, the isolation between two ports is improved from-12 dB to-16 dB. The measured results show that the antenna has an operating bandwidth of 2.95-11.2 GHz, a peak gain of 6.43 dBi, a maximum radiation efficiency of 97.96%, and an envelope correlation coefficient of less than 0.02. The results show that the proposed antenna with filtering function is a compact band-notched UWB-MIMO antenna with practical application value.