Modular floating structures provide a feasible way to solve the land scarcity in and around coastal cities. The present work investigates the hydrodynamic responses of a proposed modular floating structure system through the scale model test. The proposed system consists of several inner TLP hexagonal floating structure modules and outermost floating artificial reef modules, forming a chain-type configuration. The outermost floating artificial reef modules can play the role as a floating breakwater, meanwhile providing habitat for marine organism. The scale model test was carried out in the wave flume of Hainan University. Effects of the chain-type modular expansion on the system’s dynamic response have been extensively studied through both regular and irregular wave tests. Experimental results indicate that chain-type modular expansion notably reduce surge response and enhances the system’s survival capability under extreme sea condition. The primary experimental results in this article can offer valuable guidance for the practical application of modular floating structures in engineering.