  To understand the nature of two poles for the $\Lambda(1405)$ state, we
revisit the interactions of $\bar{K}N$ and $\pi\Sigma$ with their coupled
channels, where two-poles structure is found in the second Riemann sheet. We
also dynamically generate two poles in the single channel interaction of
$\bar{K}N$ and $\pi\Sigma$, respectively. Moreover, we make a further study of
two poles' properties by evaluating the couplings, the compositeness, the wave
functions, and the radii for the interactions of four coupled channels, two
coupled channels and the single channel. Our results show that the nature of
two poles is unique. The higher-mass pole is a pure $\bar{K} N$ molecule, and
the lower-mass one is a compositeness of mainly $\pi \Sigma$ with tiny
component $\bar{K} N$. From our results, one can conclude that the
$\Lambda(1405)$ state would be overlapped with two different states of the same
quantum number.
