A\rsenic and lead released from coal-fired power plant have caused great damage to environment and human health, making it critical to remove arsenic and lead simultaneously. The adsorption characteristics of HTMs (As2O3, Pb-0, PbO and PbCl2) on the surface of single atom iron adsorbents supported with graphene-based substrates (Fe/GS) were systematically investigated through density functional theory calculation. The magnetic properties, bonding mechanism, reaction temperature and competitive adsorption behaviors were all considered in this work. Results demonstrated that Fe/GS of single vacancy with three nitrogen atoms doping (Fe/SV-N3) shows the most excellent adsorption capacity for HTMs among four types of Fe/GS. The adsorption of HTMs on Fe/SV-N3 belongs to stable chemisorption, and the adsorption can take place spontaneously when the temperature is below 700 K. To compare with the previously studied Hg-0 system, the competitive adsorption behaviors of Hg-0 and HTMs on Fe/SV-N-3 were studied through relative adsorption ratio, Fe/SV-N-3 will preferentially adsorb Pb-0 and PbO when Hg-0 and HTMs occur simultaneously at the temperature range of 300-1000 K. Therefore, Fe/SV-N-3 is suggested to be a potential new material for gas detection and simultaneous removal of pollutants from coal-fired power plants.