Optical masquerades are a low-cost camouflage strategy that avoids the hidden objects to be recognized despite being detected. Here, we demonstrate an optical holography-based masquerade that could encode the camouflaged object ("bomb") into another uncorrelated phase object ("dog") by using transmissive dielectric metasurfaces with the total efficiency as high as 78% at visible wavelengths. The phase modulation in the encoded "dog" is realized by changing the inplane orientation of nanostructures. Illuminated by the circularly polarized light, the experimental hologram fabricated by using electron-beam lithography exhibits only the "dog" pattern when observing the surface of sample. To recover the hidden "bomb," one can observe the holographic image reconstructed at the Fresnel region, which works at the broadband spectrum from 540 nm to 680 nm. Such a technique might find potential applications in information security and military affairs.