This paper deals with the dielectric permittivity of dusty plasma in the earth’s mesosphere. We give expressions for thecomplex dielectric permittivity of dusty plasma, taking into account the effects of the dust charging process and magnetic field. We discuss the dielectric permittivity of dusty plasma in several cases, such as high frequency approximation, parallel propagation in MF/HF band, and effects of plasma movement. Finally, the expressions are employed to study the phenomenon of radar echoes from the polar summer mesosphere. We report that dielectric permittivity caused by the dust charging process gives a radar cross section proportional to ω-4 and produces a number density of charged dust that agrees with measurements of mesopheric radar echoes.