To select the cementing and coating materials of slow/controlled-release fertilizer, the natural kaoline and abandoned foam plastics were used to prepare nano-subnanocomposites through the methods of organic material intercalation, semi- emulsification, and cut at high velocity techniques. Besides, two kinds of nano-subnanocomposites were tested in this study using several instruments, including the scanning electron microscope (SEM), the X-ray diffraction (XRD), the infrared ray spectrum (IR), and the laser granularity. The main results were as follows: 1) The organic material was intercalated in the layers of kaoline clays, and the natural kaoline exfoliated into nanometer-sized layers. The organic agent and clays formed nanocomposites through hydrogen bond combination. 2) The SEM pictures of polystyrene- starch nano-subnanocomposites showed that many pores and rugas were present on the surface of film at sizes ranging from 10 to 20 nm. These nano-subnanocomposites were used as the cementing and coating materials of slow/controlled- release fertilizer. To select the cementing and coating materials of slow / controlled-release fertilizer, the natural kaoline and abandoned foam plastics were used to prepare nano-subnanocomposites through the methods of organic material intercalation, semi- emulsification, and cut at high velocity techniques. two kinds of nano-subnanocomposites were tested in this study using several instruments, including the scanning electron microscope (SEM), the X-ray diffraction (XRD), the infrared ray spectrum (IR), and the laser granularity. The main results were The organic material was intercalated in the layers of kaoline clays, and the natural kaoline exfoliated into nanometer-sized layers. 2) The SEM pictures of polystyrene-starch nano -subnanocomposites showed that many pores and rugas were present on the surface of film at sizes ranging from 10 to 20 nm. These nano-subnanocomposites were used as the c ementing and coating materials of slow / controlled-release fertilizer.