Optical rectification of laser pulses in LiNbO3 by Tilted-Pulse-Front Pumping(TPFP) to fulfill phase match is a powerful way to generate terahertz pulses. A more detailed theoretical model for TPFP scheme is presented, which then is used to analyze the terahertz generation efficiency under different pump beam polarization states. A setup to generate high-peak-power terahertz pulses by optical rectification in LiNbO3 and a time domain spectroscopy system are established. The property of generated terahertz pulses is analyzed by using terahertz camera, and the results indicate that the peak power of terahertz pulses with 0.1 THz-2 THz frequency is 0.56 MW, and the generation efficiency is 0.56‰, which is consistent with the calculated result.