Abstract: The detection and evaluation of the technical condition of fire damage is the basis for the maintenance and reinforcement of shield tunnels and their safe use. This paper establishes a comprehensive evaluation method that follows a phased and in-depth process of site investigation, testing program development, detailed testing and damage assessment and analysis, with the objective to achieve the effective detection and evaluation of the technical condition of post-fire damage in shield tunnels. A case study is carried out on a shield-driven running tunnel with a focus on the inspection method and process, inspection result analysis, grading system and treatment recommendations. The results show that the action of fire will lead to a reduction in the presumptive strength of the concrete. The carbonization depth of all the segments is between 0 and 2.0 mm, and the inspection of the shield tunnel segments by the ultrasonic phased array method has found that the action of fire has less effect on the internal compactness of the segments. The study further grades the shield tunnel by section and puts forward corresponding recommendations for treatments.