Abstract:A nonlinear finite element model for numerical analysis is developed firstly in this paper, which is validated by the data from the authors’ previous experiments. Using this reliable model, then a large amount of case study is carried out to investigate the effects of seven parameters on the rotation capacity, such as end moment ratio, force ratio, web height thickness ratio, flange width thickness ratio, slenderness ratio of compressive flange, residual stress distribution pattern and degree of connection between concrete and steel. It is found that except the degree of connection, the other parameters have significant influence. Finally,a formula for rotation capacity of the composite beams considering the above influencing parameters is proposed for engineering design.