Based　on　the　two-dimensional　discrete　element　software　UDEC,　this　article　studied　the　dynamic　response　laws　of　rock　slopes　with　inverse　nonpersistent　joints　by　the　combination　of　different　dip　angles　and　spacing　of　joint　and　length　of　rock　bridge　under　earthquake.　The　results　showed　that　the　existence　of　the　joint　surface　had　a　significant　impact　on　the　dynamic　response　of　the　slope.　When　the　dip　angle　of　inverse　nonpersistent　joint　increases　or　the　joint　spacing　decreases,　the　PGA　amplification　factor　of　each　monitoring　point　on　the　slope　surface　increases,　and　the　influence　range　is　mainly　concentrated　in　the　middle　of　the　slope　surface　to　the　slope　shoulder.　Along　the　horizontal　direction　of　the　slope,　closer　to　the　shoulder　of　the　slope,　the　PGA　amplification　factor　increases　with　the　increase　of　the　joint　dip　angle　and　the　decrease　of　rock　bridge　length　and　joint　spacing;　along　the　vertical　direction,　the　PGA　amplification　coefficient　curve　increases　first,　then　decreases,　and　then　increases　with　the　change　of　elevation,　and　the　dynamic　response　of　slope　reacts　the　most　violent　where　the　joints　are　densely　developed.