This study presents the design of a four-leaf rose-shaped coded metasurface tailored to the terahertz band with the aim of reducing radar cross section. Based on the diffuse reflection theory, the metasurface unit incorporates a built-in phase difference to create a 1-bit code. To optimize the arrangement of the metasurface coding, a genetic algorithm is integrated with the array mode. Simulation analysis shows that in the frequency range of 0.572?1.038 THz, radar cross section can be reduced by more than 10.0 dB, and the maximum can be reduced to 36.5 dB. Further research on the effect of oblique incidence shows that the performance remains stable within a range of 0?45°, although there is a weakening, but overall meet the 8 dB requirements. This coding method offers a straightforward and efficient solution for radar stealth applications, demonstrating significant potential for widespread use.