Ag nano-particles (NPs) with high dispersion possess the capacity for elemental mercury (Hg-0) removal in low temperature. To further enhance its thermo-stability and electron transfer ability, Ag-Fe3O4@rGO ternary magnetic composite was synthesized for gaseous Hg-0 capture. Results indicated that such composite has a Hg-0 removal performance with higher than 92% removal efficiency at 100 degrees C. The ternary composite has a higher Hg-0 removal performance than that of pure rGO and Ag-Fe3O4@rGO. The physical-chemical characterization results indicated that Ag nano-particles in-situ grow on the surface of Ag-Fe3O4@rGO support. The large surface area of rGO supply efficient reaction room for Hg and Ag atoms. Ag-Hg amalgam is ascribed to the mercury uptake mechanism. The spent materials can be regenerated by a simple thermal-desorption method. In addition, this magnetic material provide an opportunity that can be separated from fly ashes when used in real flue gas.