  In this paper we investigate the power spectrum of thermal fluctuations in
very early stage of viscous cosmology. When the state parameter as well as the
viscous coefficient of a barotropic fluid is properly chosen, a scale invariant
spectrum with large non-Gaussianity can be obtained. In contrast to the results
previously obtained in string gas cosmology and holographic cosmology, we find
the non-Gaussianity in this context can be k-independent such that it is not
suppressed at large scale, which is expected to be testified in future
observation.
