  The equation of state (EOS), $w(z)$, is the most important parameter of dark
energy. We reconstruct the evolution of this EOS in a model-independent way
using the latest cosmic microwave background (CMB) data from Planck and other
observations, such as type Ia supernovae (SNe Ia), the baryonic acoustic
oscillation measurements (SDSS, 6dF, BOSS, and WiggleZ), and the Hubble
parameter value $H(z)$. The results show that the EOS is consistent with the
cosmological constant at the $2\sigma$ confidence level, not preferring a
dynamical dark energy. The uncorrelated EOS of dark energy constraints from
Planck CMB data are much tighter than those from the WMAP 9-year CMB data.
