The theory ofhydroelasticity is an important branch of learning for describingthe interaction between liquid, gas and elastic structure. Itconcerns nearly every part of daily life because of itsmulti-disciplinary nature, and becomes the main research object inmany engineering fields. Based on the significance andclassification method of the nonlinear problem aboutfluid-elasticity interaction, the characteristics, state ofresearch and research methods of nonlinear hydroelasticity arepresented, covering the analytical methods, experiment methods,numerical methods and semi-analytical methods, etc. Relationshipamong the methods used to describe the medium interaction, chieflythe arbitrary Lagrangian-Eulerian method, unitedLagrangian-Eulerian method, single Lagrangian method and singleEulerian method, are discussed, together with comparisons of theirrelative advantages and disadvantages. Contents of the nonlinearhydroelasticity and its applications to aeroelasticity,hydroelasticity, entironment hydroelasticity, micro-scalehydroelasticity and vortex induced vibration are intruduced, andtask and development tendency of the nonlinear hydroelasticity arepresented.