The high noise exposure at MRT station due to the noises of the speeding trains can cause health problems for humans. This research aims to reduce the noise impact due to the speeding trains by modifying the design of the noise barrier on the outdoor MRT in Jakarta. The first step conducted in this research is a literature review on aerodynamics noise, CAD model, Computational Fluid Dynamics (CFD) and Computational Aeroacoustics (CAA), and human comfort. Furthermore, it was conducted a design of 3D noise barrier model and 3D train model in one of the outdoor MRT stations in Jakarta using the CAD software. The simulation using the CFD and CAA was implemented to acknowledge the distribution of airflow and sound occurred. The vorticity configuration resulted from the simulation was used as the foundation to modify the noise barrier. The addition of holes on the noise barrier for every 5 m is able to decrease the noise impact significantly. One of the results is that the existing aerodynamic noise of 1.2 dB up to 3.6 dB can be reduced to close to 0 dB with only minor noises around the holes. Scientifically, it can be stated that a way to lower the noise made by the train movement is by creating the right design of a noise barrier that can neutralize the source of the noise.