  We use the Monte-Carlo Markov Chain method to explore the dark energy
property and the cosmic curvature by fitting two popular dark energy
parameterizations to the observational data. The new 182 gold supernova Ia data
and the ESSENCE data both give good constraint on the DE parameters and the
cosmic curvature for the dark energy model $w_0+w_a z/(1+z)$. The cosmic
curvature is found to be $|\Omega_k|\la 0.03$. For the dark energy model
$w_0+w_a z/(1+z)^2$, the ESSENCE data gives better constraint on the cosmic
curvature and we get $|\Omega_k|\leq 0.02$.
