A new approach for the preparation of epoxy-clay nanocomposite (ECN) was developed based on utilization of water remains in the clay treatment as a carrier to improve clay dispersion and intercalation/exfoliation. A novel type organoclay was prepared by combining short and long chain molecule intercalants. The short chain intercalant provides the functionality ready to interact with the polymer, while the long one helps keep clay layers apart from each other. The micro- and nano-structures, physical and mechanical properties, and fire resistance of ECN were studied. The results indicated that the use of wet process and clay modification facilitates the dispersion intercalation/exfoliation of clay, the interaction between clay and epoxy, and subsequently improves ECN mechanical properties and fire resistance. The drying, grinding and screening steps in the preparation of organoclay could be eliminated, thereby reducing energy consumption. This method allows the solvent free in the preparation of ECN, which requires considerable time and cost for solvent removing. This also reduces ECN’s environmental impact.