Abstract: In order to compute story drift and link rotation conveniently and identify loading path and internal force distribution of V-eccentric braced steel frames( V-EBFin brief) ，the formulas of elastic axial forces of brace and shear force of link subjected to lateral loads were proposed based on the fundamental assumption of structural mechanics，and then the elastic lateral stiffness formula of V-EBF was put forward on the basis of lateral sway split method． The analysis results of 30 examples indicated that the elastic lateral stiffness formula had a higher precision． A new design method of the brace was suggested on the basis of the formulas． When lateral load distribution was known，the formula of ultimate capacity of V-EBF was derived based on virtual work principle，small deformation assumption and typical yielding mechanism of ultimate state． Pushover analysis of 10-storey V-EBF frame was conducted by finite element software SAP 2000，with which the formula of ultimate capacity was verified．