  We investigate the form factors and decay rates for the semileptonic decays
of the kaon($K_{l3})$ using the light-front quark model. The form factors
$f_{\pm}(q^{2})$ are calculated in $q^{+}=0$ frame and analytically continued
to the time-like region, $q^{2}>0$. Our numerical results for the physical
observables, $f_{-}/f_{+}|_{q^{2}=m^{2}_{l}}=-0.38$, $\lambda_{+}=0.025$(the
slope of $f_{+}$ at $q^{2}=m^{2}_{l}$), $\Gamma(K^{0}_{e3})=(7.30\pm
0.12)\times10^{6}s^{-1}$, and
$\Gamma(K^{0}_{\mu3})=(4.57\pm0.07)\times10^{6}s^{-1}$ are quite comparable
with the experimental data and other theoretical model calculations. The
non-valence contributions from $q^{+}\neq 0$ frame are also estimated.
