  The red-shift space distortions in the galaxy power spectrum can be used to
measure the growth rate of matter density perturbations delta_m. For dynamical
dark energy models in General Relativity we provide a convenient analytic
formula of f(z) sigma_8(z) written as a function of the redshift z, where f=d
ln delta_m/d ln a (a is the cosmological scale factor) and sigma_8 is the rms
amplitude of over-density at the scale 8 h^{-1} Mpc. Our formula can be applied
to the models of imperfect fluids, quintessence, and k-essence, provided that
the dark energy equation of state w does not vary significantly and that the
sound speed is not much smaller than 1. We also place observational constraints
on dark energy models of constant w and tracking quintessence from the recent
data of red-shift space distortions.
