With the development of Omni-media, live broadcast simultaneous interpreting (LBSI) has brought new challenges and opportunities for interpreters, scholars, and trainers. The characteristics of LBSI are high exposure rate, high audience expectations, unfriendly working environments and single-way communication. This study aims to conduct an analysis of the English-to-Chinese LBSI taking place in the 2020 U.S. Vice-presidential Debate by adopting the framework of Descriptive Study of Norms in Interpreting and then summarize the norms of LBSI from inter-textual, intra-textual, and extra-textual perspectives. This research contributes to the academic discourse by filling a gap in the literature on live broadcast interpreting, particularly in high-stakes political events. By examining the unique challenges of LBSI, it intends to equip interpreters with the necessary skills and strategies to manage high-pressure situations. Besides, this research endeavours to provide a deeper understanding of interpreting behaviour and activities influenced by various factors and enrich the study of fundamental sociocultural aspects in simultaneous interpreting and interpretation norms.