This paper describes the Reduced Order Modeling (ROM) for fluid rigid body interaction problem and discusses Proper Orthogonal Decomposition (POD) utilisation. The principal difficulty for using POD being the moving domains, a referenced fixed domain has been introduced. The POD has been applied for the velocity field obtained on the fixed domain. Then a method to reduce dynamical system for rigid body fluid interaction has been developed. This method consists in treating the entire fluid-solid domain as a fluid. The rigid body has then been considered as a fluid, by using a high viscosity which can play the role of a penalisation factor of the rigidity constraint. The fluid flow problem is then formulated on the reference domain and POD modes have been used in the weak formulation.