  We construct the Mellin representation of four point conformal correlation
function with external primary operators with arbitrary integer spacetime
spins, and obtain a natural proposal for spinning Mellin amplitudes. By
restricting to the exchange of symmetric traceless primaries, we generalize the
Mellin transform for scalar case to introduce discrete Mellin variables for
incorporating spin degrees of freedom. Based on the structures about spinning
three and four point Witten diagrams, we also obtain a generalization of the
Mack polynomial which can be regarded as a natural kinematical polynomial basis
for computing spinning Mellin amplitudes using different choices of interaction
vertices.
