The Casimir energy for scaler field of two parallel conductors in two-dimen
sional domain wall background, with Dirichlet boundary conditions, is calcu
lated by making use of general properties of renormalized stress-tenser. We
show that vacuum expectation values of stress-tenser contain two terms whi
ch come from the boundary conditions and the gravitational background. In t
wo dimensions the minimal coupling reduces to the conformal coupling and st
ress-tenser can be obtained by the local and nonlocal contributions of the
anomalous trace. This work shows that there exists a subtle and deep connec
tion between Casimir effect and trace anomaly in curved space-time.