Abstract: In order to determine the bearing capacity of single arch support inner portalframe,experiments on the bearing capacity of single arch support portalframe and nonlinear FEM analysis of the bearing capacity of single arch support portalframe and single MF1219 portalframe were carried out.Models of single arch support portalframe and single MF1219 portalframe were set up using ANSYS software,their eigenvalue buckling analysis was done,and their bearing capacity was obtained.Loading in grades on top ends of two uprights or the corresponding positions of both ends of the arch strengthened rod of single arch support portalframe,in which low ends of two uprights were articulated,8 single arch support portalframes bearing capacity tests were conducted.Different portalframe bearing capacity formula in JGJ 1282010 Technical Code of Portal Steel Pipe Scalffold for Building Construction was selected,and the single arch support bearing capacity was calculated.After the results of FEM analysis,experiment and calculation of bearing capacity of single portalframe were contrasted,it was proposed that forces should act on top ends of two uprights,the bearing capacity of arch support portalframe for forces acted on top ends of two uprights could be calculated by the formula in 5. 2. 1-8a of JGJ 1282010,and the reduction coefficient of the bearing capacity of arch support portalframe for forces acted on top cross bar should be 0. 3．