Noise pollution and emissions from jet engines are a pair of problems that seriously affect human health and the ecological environment. This paper presents an optimization process of aerodynamic noise reduction for a micro turbojet at the Propulsion Systems Laboratory, School of Mechanical Engineering, Hanoi University of Science and Technology. Using nozzle chevron designs and numerical simulation approach with Broadband Noise Source model, four major parameters, such as number of chevrons (NOC), nozzle chevron configuration, length and angle, are considered. The outcome results show the Surface Acoustic Power Level (SAPL) figures between prototype and parameter studies’ models. The proposal having a NOC of 8, sharp edge with length of 57 mm and angle of 100° is the best formation, where SAPL at the output cross-section diminishes from nearly 110–103 dB.