In order to avoid the meshing of discrete holes and to reduce computational cost, source term model is used for impingement/effusion double-wall cooling numerical simulation, and the effects of grid setups and heat sink discretization are analyzed. It has been concluded that overall effectiveness results can predict by source term model match the trend of experimental data.When the average number of face mesh on inlet/outlet of effusion hole is larger than a certain value, numerical results do not change with face mesh density on inlet/outlet of effusion hole.The height of first prism layer near the hot side of effusion wall has an important effect on the numerical results, and the proper setupof height is less than or equals to 0.05 hole diameter. Heat sink should be discretized on several volume cells of solid zone.