This paper has proposed an improved formula for the torque-tension relationship of bolted joints with consideration of all forces and moments acting on fasteners. Finite element analysis (FEA) is used to analyze and evaluate the relationship. An effective finite element (FE) modeling scheme which considers the helical geometry is developed. Effects of contact radii ratios of the nut bearing surface on the percentages of component torques are investigated. Percentages of component torques are calculated according to present and conventional formula, to compare with FEA results.