  The structure of $d^*(2380)$ is re-studied with the single cluster structure
in the chiral SU(3) quark model which has successfully been employed to explain
the scattering and binding behaviors of baryonic systems. The mass and width
are explicitly calculated with two types of trial wave functions. The result
shows that the $(0s)^6 [6]_{orb}$ configuration is easy to convert to the
configuration with the same $[6]_{orb}$ symmetry but $2\hbar \omega$ excitation
back and forth, however, it is seldom to turn into a two-cluster configuration
with a (1s) relative motion in between. The resultant mass and width are about
$2394$MeV and $25$MeV, respectively, and the stable size is about $0.75fm$,
which are consistent with both the results in the two-cluster configuration
calculation and the data measured by the COSY collaboration. It seems that the
observed $d^*$ is a six-quark dominated exotic state with a spherical shape and
breath mode in the coordinate space. Moreover, if $d^*$ does have $2\hbar
\omega$ excitation, the $d^* \to np\pi\pi\pi$ decay mode might be a good place
to distinguish the real structure of the observed phenomenon by COSY. The
masses of various isospin-spin states of six-light-quark systems are also
computed. It is shown that by considering the coupling with the configurations
with $2\hbar \omega$ excitations, only the mirror state with $IS$=$30$ will be
lower down to the place where whose mass is slightly higher than the value of
the $\Delta\Delta$ threshold.
