  The chiral phase transition at high temperature is investigated using the
effect ive potential in the framework of the QCD-like gauge theory with a
variational a pproach. We have a second order phase transition at $T_c=136$MeV.
We also investigate numerically the temperature dependence of condensate,
$f_\pi$ a nd $a_2(T)$(coefficient of the quadratic term in the effective
potential) and es timate the critical exponents of these quantities.
