Background: Emergency airway management outside operating room (OR) is associated with a higher incidence of difficult intubations. The Shikani optical stylet (SOS) has been shown to improve first-attempt success rates compared with the classic Macintosh laryngoscope (ML) in patients with difficult airway inside the operating room (OR). Objective: In this randomized controlled clinical trial, the effectiveness of using a SOS as the primary intubation device was assessed during urgent endotracheal intubations (UEI) in conscious, critically ill patients outside the OR. Method: Sixty conscious critically ill patients from May 2018 to March 2018 were randomly assigned to undergoing intubation guided by the SOS (group S, n = 30) or the Macintosh laryngoscope (group M, n = 30) in ChanCheng Center Hospital,. After application of airway topical anesthesia and intravenous sedatives, endotracheal intubations were performed. The primary measured outcome was first-attempt intubation success rate. Secondary outcomes included ultimate success, the number of attempts, the duration of intubation, and the adverse effects or complications of intubation. Result: The rate of successful intubation at the first-attempt was superior with the SOS as compared with the ML (93.3% vs 63.3%, P = 0.005), the average number of attempts required for successful tracheal intubation (1.0 ± 0.3 vs 1.5 ± 0.8, P = 0.004), the duration of intubation (18.8 ± 11.9 vs 26.8 ± 15.6, P = 0.028), and the incidences of hemorrhage in the oropharyngeal mucosa (0 vs 28.6%, P = 0.006) were all improved significantly with use of the SOS compared with the ML. Conclusion: This study suggested SOS could be used as the effective device when UEIs are performed by experienced operators in conscious, critically ill patients outside the operating room.