Aiming at the current situation that strain sensors of jacket platform can not cover all key positions of the structure, a method for optimal placement of strain sensors based on multi-scale simulation of structures is proposed. The pipe element and beam element are used to establish the macroscopic finite element model of the jacket platform, and the key area of the structure is determined based on static analysis. The three-dimensional solid finite element model of the key area is established, and the beam element and the solid element are coupled by the multi-point constraint method. The multi-scale modeling of the structure is completed. Through the mechanical analysis of the multi-scale model, the specific placement of the strain sensor in the key area can be determined. Taken Nanhai Lufeng 13-1 jacket platform as the object, the installation positions of the strain sensors are determined based on the proposed method, which provides scientific reference for the layout of the strain monitoring sensor of the offshore platform.