Abstract: Steel reinforced concrete structures are widely used in super high-rise buildings and large-span spatial structures due to their excellent load-bearing capacity and seismic performance. The quality defects in the pouring of steel reinforced concrete structures directly affect the performance of their mechanical properties and reduce the overall reliability of the structure. Conventional techniques are difficult to detect internal defects in steel reinforced concrete, and there are blind spots in the detection process.Ultrasonic CT method, as a new non-destructive testing method, has significant advantages in structural defect detection and provides a new technological path for detecting internal defects in steel reinforced concrete. To verify the feasibility and reliability of this detection method, this paper relies on a case study of a large commercial complex square project in Guangzhou to conduct ultrasonic CT detection on internal defects of 34 steel reinforced concrete columns, and verifies the results through core drilling. The detection results show that the ultrasonic CT method can accurately identify internal honeycomb and loose defects in steel reinforced concrete columns. Further verification by core drilling further indicates that the defects are mostly located at the interface between the steel reinforced inner wall and the concrete, verifying the effectiveness and reliability of the ultrasonic CT method for evaluating the pouring quality of steel reinforced concrete columns. The research results of this article provide practical basis and technical reference for quality inspection of similar engineering steel reinforced concrete structures, and have good promotion value and application prospects.