For investigating the fundamental characteristics and resolution limit of patterns replicated with synchrotron orbital radiation (SOR), a computer simulation program, synchrotron orbital radiation lithography simulation system (sorsis) has been developed and resulting resist pattern profiles have been analyzed in detail. Insorsis, Fresnel integrals are performed by a new model based on introducing the SOR wavelength distribution, mask contrast, and phase difference into calculations. Positive‐type resist replication pattern profiles are calculated to evaluate pattern characteristics and are compared with experimental results. These results derive a resolution limit evaluation method, representing the equationW=ε(Gλp/2)1/2.3, whereWis the minimum linewidth,Gthe proximity gap, λpthe wavelength peak, and ε the parameter mainly determined by resist characteristics and x‐ray mask absorber thickness. In this way, optimum conditions for precise pattern replication and accurate pattern profile control can be realized easily.