We suggest an approach for using microwave radiation in diagnostics of
ultracold neutral plasma. Microwave scattering from ultracold neutral plasma is
calculated . Simple formulations are get and indicate that the dipole radiation
power of ultracold neutral plasma does not depend on density profile ne(r)
and ω when ω≫ωpe0, but on the total electron number
Ne. This method provides the information of Ne and from which we can get
the three body recombination rate of the plasma, which is extremely important
in the researches of ultracold neutral plasma