Abstract: A three-dimensional axisymmetric model based on the theory of elasticity is proposed to calculate the joint stiffness of the clamped bolted joints under a separating service load and the force of the bolt head acting on the joint member is simulated by a uniform distribution of the ring-shaped normal pressure. Results of examples show that the proposed joint stiffness for bolted joints is easily calculated and the method has higher precision and stronger practical value. There is no need to assume different equivalent distribution envelopes of the compressive stress and to have to study the optimal semi-apex angle of the conical frustum for joint stiffness calculation.