  We investigate the pentaquark system $qqqs \bar q$ in a framework of chiral
quark model. Two structures, $(qqq)(s\bar{q})$ and $(qqs)(q\bar{q})$, with all
possible color, spin, flavor configurations are considered. The calculations
show that there are several possible resonance states, $Sigma \pi$ and $N
\bar{K}$ state with $IJ^P=0\frac{1}{2}^-$, $\Sigma^* \pi$ with
$IJ^P=0\frac{3}{2}^-$, $\Sigma^* \rho$ with $IJ^P=0\frac{5}{2}^-$, $\Delta
\bar{K}$ with $IJ^P=1\frac{3}{2}^-$ and $\Delta \bar{K}^*$ with
$IJ^P=1\frac{5}{2}^-$. Where the $N \bar{K}$ state with $IJ^P=0\frac{1}{2}^-$
can be used to explain the $\Lambda(1405)$, and together with another state
$\Sigma\pi$ is related to the two-pole structure of the scattering amplitude
proposed before. The decay properties of $\Lambda(1520)$ prevent the assignment
of $\Sigma^* \pi$ with $IJ^P=0\frac{3}{2}^-$ to $\Lambda(1520)$, although the
energy $\sim$ 1518 MeV of $\Sigma^* \pi$ is close to experimental value of
$\Lambda(1520)$. Other resonance states generally have a large width.
