Objective To develop a nursing protocol for unplanned emergency thoracotomy in patients undergoing video-assisted thoracic surgery (VATS), to ensure intraoperative nursing quality and patient safety. Methods A preliminary draft of a nursing protocol was developed by reviewing literature, conducting semi-structured interviews, performing participatory observation, and integrating clinical experience. Subsequently, two rounds of Delphi expert consultations were conducted to improve and finalize the protocol. Results The effective response rates for the two rounds of expert consultation questionnaires were 94.44% and 100%, respectively, with expert authority coefficients of 0.83 and 0.90. The Kendall′s W coefficients for the importance ratings of protocol indicators were 0.146 and 0.147, respectively (both P<0.05). The finalized nursing protocol for unplanned emergency thoracotomy in VATS patients comprised 4 surgical phases, 12 surgical steps, and 50 specific procedures. In initial clinical practice, the surgical team demonstrated over 95% adherence to standardized operative workflows and predefined protocols. Conclusion The nursing protocol for unplanned emergency thoracotomy in VATS patients developed in this study is scientific, feasible, and highly operational. It can provide guidance for nursing care in critical thoracic surgery emergencies.