Abstract: Performance of pipeline inner detectors directly determines if potential problems in the pipeline can be identified, but also serves as the key factor in selection of the most suitable detectors depending on specific conditions of the concerned pipeline. In this paper, key performance indicators of the pipeline inner detector, including probability of detection (POD), probability of identification (POI), probability of false calls (POFC), sampling frequency, positioning accuracy, defect types and their detection thresholds, quantitative accuracy of defect sizes and anti-disturbance ability (such as the pipeline inner wall cleanliness, the influence of flow velocity, temperature and so on), are analyzed, excavation and traction tests are proposed as techniques for verification of performances of pipeline inner detectors, and calculation methods for key performance indicators of the detectors are established. All these provide valuable references for pipeline operators in selecting suitable detector types and desirable performances for risk-based inspections.