To tackle the problem of tiny leaks in transparent soft capsules being hard to spot, a non-destructive testing method combining reflective spectroscopy with three-frequency, four-phase shift structured light 3D measurement was proposed and verified. Spectroscopy uses 484 nm as the optimal characteristic wavelength for initial capsule screening, while structured light detection conducts secondary screening based on internal depth anomalies and leak detection algorithms. By coupling the two methods, spectroscopy quickly filters out intact samples, and structured light only performs detailed checks on suspected ones. Experiments show that the combined method achieves an accuracy of 98.5%, effectively solving the issues of detection difficulty and accuracy. This provides a new approach for early leak detection in transparent soft capsules and opens up a new route for non-destructive seal evaluation in complex packaging.