The Cartesian gird has its unique advantages in computational fluid dynamics, especially for complicated boundary cases. However, the boundary layer structures can not be resolved efficiently and effectively using the Cartesian mesh. To overcome such a problem, a new boundary layer structure resolving (BLSR) algorithm is proposed on the basis of the boundary layer physics and force balance analysis. For the present two‐dimensional test cases, numerical results justify that the surface friction and drag force can be more accurately calculated without refining the near‐wall resolution. In principle this BLSR algorithm is easy to implement with negligible increase of the computational cost.</jats:p>