  The particle spectra and Hanbury-Brown Twiss (HBT) radius of Au+Au collisions
at RHIC energy are investigated by a hydrodynamical expanding source with both
shear and bulk viscosities ($\zeta$). With a large width of the ratio of
$\zeta$ to entropy density $s$, both the particle transverse momentum spectra
and the ratio $R_{out}/R_{side}$ of HBT radii in the direction of the total
transverse momentum of detected two particles ($R_{out}$) and perpendicular to
both this direction and the beam direction ($R_{side}$) become a little
steeper.
