Interdisciplinary group decision-making is core mechanism for addressing complex problems in engineering, relies on close collaboration and knowledge integration among team members. However, the heterogeneity of disciplinary backgrounds poses cognitive challenges for decision-makers when encountering knowledge from other disciplines. Existing decision-making research often falls short in capturing the cognitive dynamics of team members in real-time, thus limiting a deep understanding of the group decision-making mechanisms.This study aims to explore the relationship between engineering semantics and the neurocognitive characteristics of decision-makers in interdisciplinary group settings.Utilizing a neurocognitive science perspective, we employ functional near-infrared spectroscopy (fNIRS), a multi-attribute decision-making task (MADM) as the experimental paradigm, and leaderless group discussions (LGD) for decision-making communication.This study takes the ship design scenario as an example to simulate the realistic group decision making scenario, providing empirical and data-driven support for understanding the cognitive basis of group decision making, and providing scientific basis for intervening and optimizing the group decision making process.