Abstract: The floating offshore wind plant has grown rapidly in the past decades facing the demand of green energy resources. Compared to the onshore wind plant, the offshore wind plant is more challenging because of the harsh oceanic environment. The hydrodynamic loads are needed to be accurately quantified not only for the design of platforms but also for the routine maintenance. The methods to calculate the hydrodynamic loads are classified as the method based on potential theory model and the method based on computational fluid dynamics (CFD) model. The principles of the models are briefly introduced to highlight the different usability. Besides of the numerical methods, the physical experiments contribute to explore the dynamic loads and the structural optimization. The main technologies of physical experiments are briefly outlined by means of a study case. The paper focuses on presenting the methods on quantifying the hydrodynamic loads on the floating platform in order to promote these methods in practical engineering.