The invention discloses an aero-engine blade test piece nondestructive testing method based on a terahertz technology, which comprises the following steps: performing nondestructive testing on a sample by utilizing a terahertz signal to obtain a terahertz original detection signal; carrying out fourier transform, frequency domain deconvolution and wavelet processing on the terahertz original detection signal to obtain a characteristic signal with a high signal-to-noise ratio; performing Fourier transform on the characteristic signal with the high signal-to-noise ratio to obtain a frequency domain power spectrum, and expanding the frequency domain power spectrum to obtain a sample image; and carrying out quantitative characterization on the thickness and defects of the ceramic layer in thesample image after the imaging contrast is improved. The invention further provides an aero-engine blade test piece nondestructive testing device based on the terahertz technology. According to the method, the problems of low detection precision, limited detection range and missed detection and false detection of a traditional nondestructive detection mode can be solved, and high-precision quantitative detection of the surface, interface and internal crack defects of the thermal barrier coating and the thickness of the ceramic layer is realized.