Abstract: Aircraft flyover noise represents a specific type of transportation noise that has a considerable impact area and is challenging to effectively address through conventional noise control treatments. The objective reduction of the impact of aircraft noise may be achieved by the application of music masking, which has the effect of improving the subjective perception of the noise in question. The objective of this study is to investigate the brain response mechanism of music masking of aircraft noise. Based on the results of the preliminary experiment, five music clips with varying degrees of likability are selected as masking sounds. 20 subjects are enrolled to listen to the sounds and provide subjective ratings of the music likability and compound sound annoyance, followed by functional near-infrared spectroscopy (fNIRS) tests. Initially, group-level brain activation is obtained under different compound sound stimulations. Subsequently, the activation channels that are significantly related to music likability and compound sound annoyance, respectively, are analysed, and the relationship between co-activated regions and brain response is screened. The results of the brain response analyses indicate that the dorsolateral superior frontal gyrus and superior temporal gyrus are significantly activated in the brain regions of the subjects under the noise and compound sound stimulations. The correlation analysis results demonstrate a significant negative correlation between the magnitude of activationthe and the degree of likability, and a significant positive correlation between the magnitude of activationthe and degree of annoyance.