Submarine has been performed for national defense activities representatively. Underwater Radiated Noise (URN) which emitted during underwater vehicle operation is directly related to the survivability of the underwater vehicle. This study focused on examining the effects of surface treatment on noise aspects in submarine. Numerical simulations were conducted for two cases : smooth surface as a reference case, and V-type riblet. To solve the incompressible fluid flow passing the submarine, the Reynolds-averaged Navier-Stokes equation coupled with the k-ω SST turbulence model was used. As a result of examining the noise radiation around the submarine, it was confirmed that it was necessary to pay attention to the noise radiation effect in the middle part of the submarine body. And the results indicate that overall sound pressure level can be reduced about maximum 4 dB at far-field by applying riblet surface. This study provides more enhanced understanding about the surface design on underwater vehicles to reduce underwater radiated noise.