  We have investigated the present renormalization prescriptions of
Cabibbo-Kobayashi-Maskawa (CKM) matrix, and found there is still not an
integrated prescription to all loop levels. In this paper We propose a new
prescription which is designed for all loop levels in the present perturbative
theory. This new prescription will keep the unitarity of the bare CKM matrix
and make the amplitude of an arbitrary physical process involving quark mixing
convergent and gauge independent.
