The adsorption and rep lacement behaviors of arsenic on the reconstructed Si (211) surface have been simu-lated by the CASTEP software. By calculating several possible structures as well as analyzing the energies and bond lengths,We have investigated the passivation mechanisms of the arsenic on the si surface. ThenWe have studied the adsorption behaviors of. tellurium and cadmium on the clean and As-passivated Si ( 211) surface. The simulation results obtained in current study show that single Cd or Te atom can be adsorbed on the clean Si (211) stably, but they are hard to be adsorbed on the passivated area of the As2passivated Si (211) surface.