  We propose a new method to renormalize lattice operators. The method is based
on the technique to compute the spectral sum appearing in the
Shifman-Vainshtein-Zakharov QCD sum rule from lattice correlators. The
application of this technique to the light quark system is useful for operator
renormalization as well as for the test of perturbative QCD and OPE. We
determine the renormalization constant of the vector current and discuss
extensions to other current operators.
