  We study the power of current and future observational Hubble parameter data
(OHD) on non-parametric estimations of the dark energy equation of state,
$w(z)$. We propose a new method by conjunction of principal component analysis
(PCA) and the criterion of goodness of fit (GoF) criterion to reconstruct
$w(z)$, ensuring the sensitivity and reliability of the extraction of features
in the EoS. We also give an new error model to simulate future OHD data, to
forecast the power of future OHD on the EoS reconstruction. The result shows
that current OHD, despite in less quantity, give not only a similar power of
reconstruction of dark energy compared to the result given by type Ia
supernovae, but also extend the constraint on $w(z)$ up to redshift $z\simeq2$.
Additionally, a reasonable forecast of future data in more quantity and better
quality greatly enhances the reconstruction of dark energy.
