  We study chiral expansion at $m_\rho$-scale in framework of chiral
constituent quark model. The lowest vector meson resonsances are treated as
composited fields of constituent quarks. We illustrate that, at energy scale of
$\rho$-meson mass, the chiral expansion expansion converges slowly. Therefore,
it is possible to construct a well-defined chiral effective field theory at
this energy scale, but high order correction of chiral expansion must be
included simultanously. The one-loop correction of pseudoscalar mesons is also
studied systematically. The unitarity of the model is examined and Breit-Wigner
formula for $\rho$-meson is obtained. The prediction on on-shell
$\rho\to\pi\pi$ and $\rho\to e^+e^-$ decays agree with data very well.
