Recently, the left line shield tunneling of the Nanwen section of the Shenyang Metro Line 3 project undertaken by the Urban Rail Transit Company of China Railway 15th Bureau Group successfully broke through, accumulating valuable experience for subsequent construction, creating a good reputation for the Urban Rail Transit Company in Shenyang metro construction, and contributing to the Group's value creation initiative through practical actions. After the shield machine was launched, the project management team actively sought the optimal tunneling parameters under the geological conditions, strengthened construction organization and management, achieved an excellent average daily advance of 12.5 rings in the short section, and overcame three construction challenges. First, it successfully achieved launch within the small space of an intermediate shaft and mined tunnel. Due to the limited space in the mined tunnel, the project department simulated the layout of the shield machine's trailer section before the machine entered the site, and successfully sent the trailer into the mined tunnel by adjusting the trailer structure and the positions of equipment on the trailer. Second, it successfully achieved shield launch under ultra-low temperature conditions. Facing a low temperature of -15°C, systems on the shield machine such as circulating water, foam, and grouting were prone to functional failures such as freezing and reduced grout activity. To this end, the project adopted multiple measures including covering, pipeline insulation and heating, and adjusting the grout mix ratio, ensuring the normal operation of all systems during winter launch. Third, it successfully achieved launch on a small curve and steep slope. The shield launch route was located on a 315m right-turn horizontal curve and a 26% downhill vertical curve. To ensure the construction quality of the formed segment rings, data simulation was used to adopt secant launch and strictly control the construction parameters of each ring. The formed segment rings had no quality issues such as limit intrusion or water leakage, and received favorable comments from all parties.