  We study the thermal and curvature effect to spontaneous symmetry breaking in
phi^4 theory. The effective potential is evaluated in D-dimensional static
universe with positive curvature R X S^{D-1} or negative curvature R X H^{D-1}.
It is shown that temperature and positive curvature suppress the symmetry
breaking, while negative curvature enhances it. To consider the back-reaction
we numerically solve the gap equation and the Einstein equation simultaneously.
The solution gives the relationship between the temperature and the scale
factor.
