Terahertz digital holography is one of the research hotspots in the terahertz imaging field over the world nowadays. The real reconstructed image was used as the research object, which was achieved by the continuous terahertz inline digital holographic imaging system, and the de-noising research was studied based on wavelet transform. Wavelet threshold technique and the homomorphic filtering based on wavelet were applied to denoise the image, with hard threshold and soft threshold technique respectively, by "bior2.2" and "sym4" wavelet base. Then the denoising result was quantitatively assessed. The experimental results show that the homomorphic filtering based on wavelet has the best de-nosing performance for the reconstructed image of terahertz continuous inline digital hologram, which works with soft threshold method and the "bior2.2" wavelet basis.