Abstract: Atmospheric limb radiation model in UV band was established based on transport theory, and spherical atmospheric accumulation solution method is proposed. According to Snell's law of refraction and spherical trigonometry formula, the calculation method of refractive path in limb geometry is presented. The calculation results of limb transmittance and limb radiance in typical atmospheric modes and tangent heights are given, and the impact of refractive effect is analyzed. The calculation results can provide a reference for space borne optical detection system in simulation and application and the study of global environmental change and climate prediction.