  The QCD one-loop renormalization is restudied in a mass-dependent subtraction
scheme in which the quark mass is not set to vanish and the renormalization
point is chosen to be an arbitrary timelike momentum. The correctness of the
subtraction is ensured by the Ward identities which are respected in all the
processes of subtraction. By considering the mass effect, the effective
coupling constant and the effective quark mass are given in improved
expressions which are different from the previous results.
