Introduction:　The　issue　of　population　aging　is　increasingly　prominent,　presenting　unprecedented　challenges　and　pressures　on　urban　medical　resources.　The　equity　and　convenience　of　medical　services　for　older　adults　have　emerged　as　critical　concerns　for　urban　planners.　While　previous　research　on　medical　accessibility　for　older　adults　has　yielded　fruitful　results,　it　has　lacked　a　thorough　analysis　of　the　quantitative　relationship　between　revealed　and　potential　accessibility　across　urban　spaces,　as　well　as　the　influencing　factors　leading　to　the　spatial　heterogeneity　of　these　two　types　of　accessibility.　Methods:　This　study　calculates　the　ratio　of　revealed　to　potential　accessibility　based　on　multisource　data,　thereby　identifying　the　allocation　of　medical　resources　in　different　sub-districts　in　Beijing.　Furthermore,　an　extreme　gradient　boosting　model　is　used　to　investigate　the　non-linear　associations　between　the　potential　influencing　factors　and　the　ratio　of　revealed　to　potential　accessibility.　Results:　The　results　revealed　a　significant　spatial　disparity　between　potential　accessibility　and　revealed　accessibility　and　identified　the　threshold　effects　of　influencing　factors　contributing　to　the　accessibility　ratio　of　revealed　to　potential　accessibility.　The　density　of　bus　stops,　vehicle　ownership,　and　density　of　roads　are　the　top　three　among　the　influencing　factors　in　terms　of　their　relative　importance　in　influencing　the　accessibility　ratio.　Conclusions:　The　threshold　effect　should　be　considered　when　implementing　planning　adjustments,　as　simply　increasing　or　decreasing　the　values　of　specific　built　environment　variables　may　not　result　in　a　corresponding　improvement　in　medical　accessibility　for　older　adults.　With　limited　resources,　enhancing　the　planning　and　construction　of　transportation　infrastructure　is　more　efficient　in　reducing　the　discrepancy　between　revealed　accessibility　and　potential　accessibility　compared　to　other　methods.