A novel boundary integral equation based method is proposed to compute the equivalent surface impedance in this letter.Different from the traditional algorithm to discretize the conductor cross section, the proposed method only discretizes the contour of the conductor cross section, thus reducing the computer memory and time cost.The loss characteristics of conductor describing the skin effect is taken into account through Greens function.The equivalent surface impedance model can be utilized to simplify electromagnetic simulation only using electric field integral equation.Numerical results show that the proposed method is both efficient and accurate in a broadband frequency, which can be used for modeling of 3-D interconnects and integrated passive structures.