Abstract: The microbiota-gut-brain axis (MGBA) constitutes a complex network through the interconnected mechanisms of the neurological, endocrine, and immune systems. MGBA has been established as a vital theoretical framework to elucidate the impact of gut microbiota on the biological characteristics of malignant brain tumors. A significant portion of existing research explores the influence of microbiota on brain tumors through the immunological pathway, thereby overlooking the intricate composition of the MGBA. Our study revisits the MGBA paradigm with an emphasis on the modulatory role of gut microbiota on cerebral neurotransmitters, including dopamine, serotonin, and glutamate. Moreover, we further analyzed their subsequent regulation of tumor cell proliferation and invasion. Furthermore, the investigation aims to enhance our knowledge of how gut microbiota may modulate the progression of malignant brain tumors, thus presenting innovative perspectives and directions for basic and clinical oncology research in the future.