Abstract: In this paper graybody factors and Hawking radiation and evaporation rates of charged massive spin 1/2 particles in the background of dilaton black holes are obtained. By using these solutions, effect of fermions in behavior of dilaton black holes compared with scalars is studied. Behavior of effective potentials in term of various coupling constants and charges are studied numerically and analytically. Unlike other black holes at the event horizon the effective potential for spin 1/2 particles no longer vanishes in extremal case for a>= 1. Hence in calculations of Hawking radiation we obtained a deviation in expected Hawking radiation spectrum. The results are analyzed in term of different dilaton coupling constant and black hole charge. Obtained effective potential diverges and greybody factors vanish for spin 1/2 particles in a>1 as the black hole approaches to extremality. We obtained that the area of dilaton black hole has crucial rule on greybody factors. For better approximation backreaction correction is taken into account. By this correction a cutoff frequency at high frequency on greybody factors is obtained. In analytical calculation of greybody factors Rosen-Morse potential compared with numerical calculation is taken into account. By increment of coupling constant energy flux increases and for infinite coupling constant approaches to a constant value. As the charge of black hole increases energy flux decreases. While for a>1 and in near extremality energy flux increases along with increment of black hole charge. But, because of existence of a cutoff frequency in greybody factors at a>1, this story does not end just here. This cutoff frequency reduces by increment of charge and in the case of near extremal, it suppresses and turns off the hawking radiation of black hole.