In　order　to　study　the　influence　of　different　loadsand　cross　section　size　on　RC　beam　plastic　hinge,　a　total　of　13　reinforced　concrete　beamswith　5　section　sizeswere　tested　under　monotonic　loading,　and　the　calculation　of　pure　bending　plastic　hinge　parameters　considering　size　effect　isstudied　based　on　experimental　data.　The　results　show　that　the　plastic　rotation　capacity　of　plastic　hinge　zone　exists　significant　size　effect,　and　a　way　to　calculate　inelastic　curvature　and　inelastic　equivalent　corner　is　put　forward,　measured　data　and　calculated　results　are　in　good　agreement.