We first state that our presentation in DIS2018 conference includes two aspects of research: the underlying events and the photon structure which has been published in the earlier DIS proceeding in 2016, so in this proceeding, we will focus on the study of underlying events.In high energy physics, the underlying event is everything except the two outgoing hard scattered jets, it includes the contributions from beam remnant as well as initial and final-state radiation. The behavior of underlying event at a future Electron Ion Collider (EIC) is studied in this proceeding. We apply both "region method'' and "off-axis method'' to measure the underlying event with pseudo data generated from PYTHIA. It indicates that these two methods are consistent, and the final results are comparable with those measured from STAR at similar center-mass energy.