The deflector obtains the directional propagation of electromagnetic wave, and plays an important role in sensing and optical communication. The chromatic problem causes the deflection angle varying with wavelength, which limits the application scope of the deflector. In order to achieve achromatic aberration, in this paper, we analyze the physical mechanism of the chromatic aberration and realize achromatic terahertz deflectors using the geometric and resonant compensation phase, which are composed by the all-dielectric metasurface. In addition, the simulations of the achromatic effect are carried out by the finite difference time domain (FDTD) method within a continue frequency range from 0.5 to 1.1 THz.