A single Halo fully depleted strain Si Silicon-On-insulator (SOI) structure, which has the advantages of strained Si, Halo doping, and SOI structure, is proposed to improve driving current, suppress the short channel effect (SCE) and drain induced barrier lowering (DIBL) effect. A two-dimensional analytical model for the surface potential, the surface electric field and the threshold voltage is proposed by solving Poisson's equation. The effects of Ge fraction in the relaxed layer on surface potential and threshold voltage are investigated. In the paper we analyze the influence of drain voltage on surface potential. Finally the effects of Halo doping on threshold voltage and DIBL are investigated. The results show that the novel device can suppress the short channel effect and DIBL effect, and increase carrier transport speed.