Abstract: To investigate the deformation characteristics of the surrounding rock in the unsupported roof zone at the tunneling head face during roadway excavation, the 30304 return air roadway of Yanghuopan Coal Mine is taken as the engineering background. Based on the elastic beam theory, a mechanical calculation model for the roof at the tunneling head face is established, and the deflection curve equation for the temporary support zone and the discriminant formula for the maximum unsupported roof distance are derived. Combined with the FLAC^3D numerical simulation method, the influence of the unsupported roof distance on the stress field and plastic zone evolution of the surrounding rock is systematically analyzed. The results show that when the safety factor is 1.3, the theoretical maximum unsupported roof distance is calculated to be 2.62 m. Numerical simulation reveals that when the unsupported roof distance exceeds 2.5 m, the stability of the surrounding rock deteriorates significantly, manifested by an accelerated increase in the peak vertical stress of the two sidewalls, a larger attenuation amplitude of the horizontal stress in the roof, and the plastic zone height extending to 1.4 m with a "four-corner arch" type failure. Controlling the unsupported roof distance within 2.5 m can reduce the stress concentration factor of the surrounding rock and shrink the extent of the plastic zone.