This thesis is mainly surveyed the characteristics of polycrystalline silicon thin film transistor (TFT) putting forward and probing into four kinds of novel buried-oxide structures. With these structures, we can improve the shortcoming of the traditional polycrystalline silicon TFT, like leakage current (On/Off state current), subthreshold swing, floating body effect (kink effect), self-heating effect, and short channel effect etc.. Novel buried-oxide polysilicon thin-film transistors (poly-Si TFTs) are proposed and demonstrated to be superior to their conventional counterparts. Furthermore, these novel structures are simple to fabricate, practical, and completely compatible on CMOS technology. Otherwise, the poly-Si TFT with/without NH3 annealing and body implantation, and their corresponding effects, have also been investigated and discussed in depth.