A nonlinear finite elements analysis was carried out to investigate the failure modes and the ultimate strength of gusset plate to CHS KKjoints. The effects of web loading proportion, geometric parameters and axial stress in chord on the ultimate strength were considered. It was found that the ultimate strength of gusset plate to CHS KKjoints was greatly decreased with the increase of web loading proportion when the proportion value was positive; however, the web loading proportion had less effect on the ultimate strength when the proportion value was negative. And with the varying of web loading proportion, the effect of the axial stress in chord on the ultimate strength of KKjoints had a complex effect on the joint mechanic behavior. Based on the regression analysis, a formula was proposed for predicting the ultimate strength of gusset plate to CHS KKjoints.