As one of the most commonly used fittings in transmission lines, suspension clamp usually led to unnecessary electromagnetic loss due the unreasonable material selection and structure design, which not only wasted electric energy, but also caused electromagnetic interference on the surrounding environment, This paper carried out the electromagnetic simulation research on the suspension clamp and conductor nearby with three dimensional finite element simulation technology base on ANSYS software, analyzed the related laws of suspension clamps magnetic field and eddy current distribution in AC transmission lines, as well as the electromagnetic loss. Then, the simulation result was compared with the experiment and the accuracy of simulation was verified. The calculation and comparison results on suspension clamps with different materials show that suspension clamp made of aluminum alloy has less electromagnetic loss than the one made of ferromagnetic material. According to the simulation research on suspension clamps with different structures, it is show that the grooving can properly reduce the eddy current density and electromagnetic loss in the appropriate place where the value is abnormal. On the basis of the above analysis, some optimization suggestions were proposed for the decrease of electromagnetic loss.