The effects of heat treatment on the electrical properties of strained-Si/SiGe-on-insulator (SGOI) devices were examined. We proposed the optimized heat treatment processes for improving the back interfacial electrical properties in SGOI-MOSFET. By applying the additional pre-RTA (rapid thermal annealing) before gate oxidation step and the post-RTA after source/drain dopant activation step, the electrical properties of strained-Si channel on $Si_{1-x}Ge_x$ layer were greatly improved, which resulting the improvement of the driving current, transconductance, and leakage current of SGOI-MOSFET.