Based on the fundamental principles of nonlinear optics, the properties of terahertz (THz) radiation generated through the optical rectification of shaped ultrashort laser pulses interacting with lithium tantalate (LiTaO₃) crystal are systematically studied. The influence of laser pulse shaping parameters on the amplitude and spectral distribution of THz radiation is analyzed through numerical calculations. A 4F pulse shaping technique is employed to change and control the optical rectification process in LiTaO₃ crystal, thereby changing the spectrum and amplitude of the generated THz pulses. The results reveal that due to the phonon absorption of the crystal at around 4.4 THz, the THz radiation produced by optical rectification can be divided into high-frequency and low-frequency bands. With shaped ultrashort laser pulses, both the central frequencies and amplitudes of the high-frequency and low-frequency components of THz pulses can be modified, enabling the generation of spectrally tunable THz pulses. This study provides a theoretical foundation for developing tunable broadband THz pulse radiation based on the interaction between shaped ultrashort laser pulses and crystals. Additionally, it offers a practical solution for this development.