  Utilizing the CLASS statistical sample, we investigate the constraint of the
splitting angle statistic of strong gravitational lenses(SGL) on the
equation-of-state parameter $w=p/\rho$ of the dark energy in the flat cold dark
matter cosmology. Through the comoving number density of dark halos described
by Press-Schechter theory, dark energy affects the efficiency with which
dark-matter concentrations produce strong lensing signals. The constraints on
both constant $w$ and time-varying $w(z)=w_0+w_az/(1+z)$ from the SGL splitting
angle statistic are consistently obtained by adopting a two model combined
mechanism of dark halo density profile matched at the mass scale $M_c$. Our
main observations are: (a) the resulting model parameter $M_c$ is found to be
$M_c \sim 1.4$ for both constant $w$ and time-varying $w(z)$, which is larger
than $M_c \sim 1$ obtained in literatures; (b) the fitting results for the
constant $w$ are found to be $w =-0.89^{+0.49}_{-0.26}$ and $w
=-0.94^{+0.57}_{-0.16}$ for the source redshift distributions of the Gaussian
models $g(z_s)$ and $g^c(z_s)$ respectively, which are consistent with the
$\Lambda \rm CDM$ at 95% C.L; (c) the time-varying $w(z)$ is found to be for
$\sigma_8 = 0.74$: $(M_c; w_0, w_a)=(1.36; -0.92, -1.31)$ and $(M_c; w_0,
w_a)=(1.38; -0.89, -1.21)$ for $g(z_s)$ and $g^c(z_s)$ respectively.
