Abstract: To address the challenges posed by strong geometric interference and difficulties in parameter adaptation during in-service detection of natural gas pipeline welds, this work proposes a collaborative design method integrating coil topology innovation and response surface methodology-based parameter optimization. At the topology configuration level, two novel array eddy current testing modes, namely the long-distance single driver (LSD) and the short-distance double driver (SDD) have been developed. The LSD mode suppresses geometric noise through symmetric differential reception and gradient field operations, and the SDD mode establishes a high-gradient detection window in the weld center region via a dual-excitation coil phase interference mechanism, achieving a 3.6-fold sensitivity improvement over conventional methods. For parameter optimization, the nonlinear coupling effects of excitation frequency, amplitude, and gain are systematically analyzed using Box-Behnken experimental design combined with response surface methodology (RSM). The approach achieves a detection signal-to-noise ratio of 7.95 dB and a 100% defect detection rate. The synergy between physical-layer topology modulation and algorithmic-layer parameter optimization significantly enhances the reliability of complex weld defect detection, providing an engineered solution for in-service inspection of oil/gas pipelines.