In order to limit the Floating Production Storage and Offloading (FPSO) to a specific area, a set of tug arrangement scheme for FPSO limit operation is proposed and the numerical simulation of the scheme is carried out. Based on the MOSES software, the FPSO, mild steel arm, mooring leg and towing cable constitute a multi rigid body coupling calculation model for limit analysis. According to different loading and environmental conditions, the motion response function Response Amplitude Operator (RAO) is calculated by frequency domain analysis, and the motion response of FPSO is simulated in time domain. The motion response and the force on the towing cable are statistically analyzed by the statistical method, and the maximum value is calculated. A reference for the safety and feasibility of limit operations could be provided by the calculation results.