This study involved a comprehensive investigation aimed at achieving efficient multi-millijoule THz wave generation by exploiting the unique properties of cylindrical GaAs waveguides as effective mediators of the conversion of laser energy into THz waves. Through meticulous investigation， valuable insights into optimizing THz generation processes for practical applications were unearthed. By investigating Hertz potentials， an eigenvalue equation for the solutions of the guided modes （i.e.， eigenvalues） was found. The effects of various parameters， including the effective mode index and the laser pulse power， on the electric field components of THz radiation， including the fundamental TE （transverse electric） and TM （transverse magnetic） modes， were evaluated. By analyzing these factors， this research elucidated the nuanced mechanisms governing THz wave generation within cylindrical GaAs waveguides， paving the way for refined methodologies and enhanced efficiency. The significance of cylindrical GaAs waveguides extends beyond their roles as mere facilitators of THz generation； their design and fabrication hold the key to unlocking the potential for compact and portable THz systems. This transformative capability not only amplifies the efficiency of THz generation but also broadens the horizons of practical applications.