The renormalized energy-momentum tensor and Casimir effect of Dirac field in general asymptotic flat two-dimensional black hole backgrounds with Dirichlet boundary conditions are calculated using the general properties of the renormalized energy-momentum tensor. The general formulas of the renormalized energy-momentum tensor is given and the corresponding Casimir forces in many specific asymptotic flat black hole backgrounds are obtained. The relations of the renormalized energy-momentum tensors and Casimir effect with vacuum，Hawking radiation and trace anomaly are investigated respectively and the corresponding computation results are obtained.