In the construction of large-scale onshore projects in overseas areas with high labor costs, modularization has become a preferred construction method. Through the case analysis on an overseas natural gas to methanol project, the characteristics of the modularization method are discussed from various aspects. Firstly, the preconditions that need priority are analyzed; then the influencing factors that need special attention in the process are discussed; by comparing and calculating the foreign and domestic labor costs, it can be intuitively seen that there is a huge gap between the two; by comparing the costs of materials and labor in traditional construction and modular construction, analysis is focused on the significant advantages of modularization in terms of reducing project costs. After cost comparison and analysis, it can be clearly seen that the use of modular construction can greatly reduce project investment and have a great impact on labor costs.