The structural and electrical properties of titanium dioxide(TiO2) thin films deposited on p-type (100) si and 4$^{circ}$off(100) Si substartes by metalorganic chemical vapor deposition (MOCVD) have been studied with post rapid thermal annealing. TiO2 thin films of anatase phase were grown at 300-500$^{circ}C$ using titanium post rapid thermal annealing at a temperature of 800$^{circ}C$ for 30sec. rutile phase was observed in the condition of the deposition temperature over 350$^{circ}C$ in the ambient air atmosphere and at 500$^{circ}C$ in cacuu,. SEM and AFM study show-ed surface roughness were increased slightly from 40${AA}$to 55${AA}$ after annealing due to grain growth and phase transformation. From capacitane-voltage measurement of Al/TiO2./p-Si structure after annealing we obtained ideal capacitance-voltage characteristics of MOS structure with dielectric constant of 16-22 in case of (100) Si and about 30- in case of 4$^{circ}$off(100) Si but showed the higher leakage current.