  We investigate whether interaction between massive neutrinos and quintessence
scalar field is the origin of the late time accelerated expansion of the
universe. We present explicit formulas of the cosmological linear perturbation
theory in the neutrinos probes of dark-energy model, and calculate cosmic
microwave background anisotropies and matter power spectra. In these models,
the evolution of the mass of neutrinos is determined by the quintessence scalar
field, which is responsible for a varying effective equation of states:
$\omega_{eff}(z)$ goes down -1. We consider several types of scalar field
potential and put constraints on the coupling parameter between neutrinos and
dark energy. By combining data from cosmic microwave background (CMB)
experiments including the WMAP 3-year results, large scale structure with
2dFGRS data sets, we constrain the hypothesis of massive neutrinos in the
mass-varying neutrino scenario. Assuming the flatness of the universe, the
constraint we can derive from the current observation is $\sum m_{\nu} < 0.45$
eV at 1$\sigma$ (0.87 eV at 2$\sigma$) confidence level for the sum over three
species of neutrinos. The dynamics of scalar field and the impact of scalar
field perturbations on cosmic microwave background anisotropies are discussed.
We also discuss on the instability issue of the our model and confirm that
neutrinos are stable against the density fluctuation.
