  We present an exact thick domain wall solution with naked sigularities to
five dimensional gravity coupled with a scalar field with exponential
potential. In our solution we found exactly the special coefficient of the
exponent as coming from compactification of string theory with cosmological
constant. We show that this solution is self-tuning when a 3-brane is included.
In searching for solution with horizon we found a similar exact solution with
fine-tuned exponent coefficient with an integration constant. Failed to find a
solution with horizon we prove the non-existence of horizons. These naked
sigularities actually can't be resolved by horizon. We also comment on the
physical relevance of this solution.}
