Highway tunnel is an important part of modern transportation infrastructure,and is also faced with potential safety hazards caused by structural defects while ensuring traffic safety and smoothness.First,through literature research and field investigation,this paper will introduce the details of tunnel lining defect detection.Through the analysis and comparison of the experimental results,this paper concludes that the presence of defects has a certain impact on the highway tunnel structural safety.This paper summarizes the effective detection of structural defects in highway tunnels and comprehensively analyzes the impact of these defects on the tunnel structural safety.