The invention relates to a non-destructive detection method based on the micro power spectrum density and an application thereof. The detection method comprises the steps of 1, data acquisition; 2, preprocessing and processing analysis for original acquisition data; 3, result map drawing; 4, analysis and interpretation. The application of the micro power spectrum density based detection method isthat the detection method is used for detecting longitudinal and transverse inhomogeneous geologic bodies within a depth range of 100m at the shallow earth's surface in urban engineering construction.The advantages lie in that a non-destructive detection method is provided for longitudinal and transverse inhomogeneous geologic bodies of the shallow earth's surface in urban engineering construction, and the detection method has the advantages of convenient field collection, high detection precision, high resolving power and abilities of shortening the investigation period, reducing the engineering cost and reducing the exploration risk and the like.