Abstract: The modular design and manufacture of yachts is an important technical approach to expand the scale and develop with high quality in the future yacht industry, but the environmental effect assessment of its product and process characteristics has not been carried out. In this paper, the environmental impact assessment of a type of detachable modular yacht is carried out. GaBi software is used to model and analyze the whole life cycle of the modular yacht. The results show that the environmental impact of the modular yacht in the construction stage is higher than that of the non-modular yacht. When the dismantling and recycling efficiency reaches 72.69%, the environmental impact caused by modular yachts in the whole life cycle is the same as that of non-modular yachts, and the modular design of future yachts can reduce the environmental impact by improving the dismantling and recycling efficiency. Monte Carlo simulation was used to analyze the uncertainty of its life cycle evaluation. The work revealed that global warming is the most serious and acidification is the second among all kinds of environmental impacts produced in the life cycle of detachable modular yachts. The results of the work in this paper can provide design reference for modular yachts and guidance for low-carbon operation of yachts.