We investigate the electronic-transport properties of two-dimensional monolayer films from Au-P-Au molecular junction to Au-Si-Au molecular junction using elastic scattering Green’s function theory.In the process of replacing the P atoms with Si atoms every other line from the middle of monolayer blue phosphorus molecular structure,the substitution of Si atoms changes the properties of Au-P-Au molecular junction significantly.Interestingly,the current value has a symmetric change as a parabolic curve with the peak appearing in Au-Si1 P1-Au molecular junction,which provides the most stable current of 15.00nA in a wide voltage range of 0.70-2.70 V.Moreover,the current-voltage characteristics of the structures indicate that the steps tend to disappear revealing the property similar to metal when the Si atoms dominate the molecular junction.