Within construction industry developing rapidly in domestic, long span buildings and high-rise buildings emerge in endlessly. Steel tubular structures are increasingly widely used for its unique advantages. Thanks to the situation, flange-plate connections become more and more popular as an important solution of splicing steel tubular structures. The connections provide easy and fast installation，nice shape, simple constitution for tubular structures without the need for welding. Typical loading situations include axial tension force and moment for flange-plate connections. The loading capacity under axial tension was studied by many scholars. Unfortunately, study on flexural capacity of flange-plate connections is limited. This situation limits the generalization of the nice connections. As can be seen from the review on flange-plate connections, there is no doubt that doing research on flexural capacity of flange-plate connections is necessary. Previous studies on axial loading capacity of flange-plate connections can provide helpful options of research for this work. One of the options is to observe the prying forces caused by flange-plates’ deformation, for prying is an important influencing factor on axial loading capacity of flange-plate connections which can reduce capacity of the connection. It is same as axial loading case that prying forces exists in the tensile region of flange-plate connections under bending moment, and they should be paid attention because they can reduce the flexural capacity of the connections with no doubt. This paper addresses on four basic kinds of flange-plate connection’s flexural capacity and is developed by means of finite element method with finite element program ANSYS. Related FE models are established and checked compared with experimental results. Based on the reliable FE models, the subsequent analysis especially studies on the effect factors of prying force in the tensile region of connection in the tensile region of connection. The corresponding parametric analysis is developed, including the thickness of flange-plate, the ratio of outer and inner diameter of flange-plate, material property of bolts, etc. Finally the key effect factors are found. The conclusions from this paper can provide references for Engineering Design.