Applying the ANSYS FE, the paper analyzed the stability behavior of welded Q460 I-section columns with slender web under biaxial bending and proposed practical formulas for predicting the stability capacities of such members.Parameters considered in the analysis included web slenderness, member slenderness, flange slenderness and loading eccentricities. The results showed that the detrimental effect of web local buckling on the stability capacity of the member is more significant for axial load dominated members than for bending moment prevailed members. Comparison to the current code method showed that the later can not accurately predict stability capacities of such members. The proposed modified DSM method demonstrates rather good accuracy, meanwhile is safe.