After an offshore topside module is constructed on land, it is moved to the transportation barge by the load-out operation. Once the module arrives at the field, the floating crane is used to install the module on the sub-structure such as the jacket. For the safe operation, methods for the load-out, transportation, and installation should be analyzed in advance. Flexible multibody dynamics which is theoretically based on ANCF (Absolute Nodal Coordinate Formulation), and collision dynamics which is based on the non-interpenetration constraints are developed for physics-based simulation. By using the developed program, we analyzed dynamic effects during load-out, transportation, and installation of the topside module. For the load-out operation, MTPs (Modular Transporters) are modeled to lift the topside module and to move toward the transportation barge. The transportation barge and the quay are connected by link beams which are modeled by flexible bodies. Finally, during the load-out operation, dynamic loads on the deck and the link beams are calculated. Secondly, during the transportation, dynamic loads due to the wave-induced motion between the barge and the module due to sea fastening are calculated. Thirdly, the motion of the module lifted by the floating crane is checked according to the environmental conditions. As a result, we can evaluate safe environmental conditions and dynamic loads.