Oil and gas pipelines are susceptible to defects throughout their service life due to manufacturing processes and complex environmental conditions, often face incidents such as ruptures. Consequently, non-destructive testing is crucial for ensuring pipeline integrity. This study examines the impact of crack defects on the potential field through the direct current potential drop method, facilitating the development of a multi-probe defect detection technique. Finite element analysis of flat plate specimens with defects disclosed a pronounced potential difference in areas with defects compared to those without. By partitioning the specimen area according to the detection scope of multiple probes, a novel multi-probe detection method was devised. Detection of a defect triggers the calculation of the defect influence factor, k; in areas without defects, k values typically range from 0.8 to 1.2, whereas in the vicinity of defects, they exceed 2. This variance in k values aids in approximating the defect's location and size. Additionally, a multi-probe detection experimental platform was established, confirming that potential differences near defects are significantly higher than in other areas, aligning with the findings from finite element analysis. Notably, the potential difference was substantially greater in defect areas, with k values in unaffected zones ranging from 0.75 to 1.2, and surpassing 1.5 in defect areas. The analysis of the distribution of k values offers insights into the defect's precise location and size, with an accuracy deviation of about 3-5mm.