This paper presents a new inductance-capacitance non-destructive detection technique with a form of planar dual-mode sensor. The detection principle of the sensor in mode-L and mode-C was analyzed, and the feasibility of this new combination of inductance and capacitance nondestructive detection technique was demonstrated. A PCB sensor was designed and manufactured, a further research on the characteristic physical field of the designed sensor using finite element simulation software was presented. A suitable detection system was developed to realize this new dual-mode detection technique using this dual-mode detection sensor. Typical test pieces were prepared and tested. The detection results show that the proposed new inductance-capacitance technique can detect typical defects in both insulator and conductor layers of the insulator-conductor hybrid structure with a good balance of inductance and capacitance performance, indicating that this new detection technique can be further used for insulator-conductor hybrid structures non-destructive testing with the potential for structure detection, quantitative evaluation, damage imaging and other applications.