To improve the dispersion of nanoparticles and avoid the recycle process of nanomaterials for water treatment,nanocomposite materials were prepared and a new photocatalytic reactor was designed. SEM, XRD and specific surface area tester were employed to characterize the as-prepared nanometer TiO_{2/diatomite composites and nanometer TiO2/SiO2 composites. Results show that the as-prepared nanocomposite materials are in the nature of very fine nanometer particles in diameter and high specific surface area and pore volume. After 6 times reusing of the as-prepared nanocomposite materials, the degradation efficiencies of TNT wastewater are kept over 90 percent by loading it on the photocatalytic reactor,while the degradation efficiencies are decreased quickly from about 97 percent to about 50 percent by dispersing nanocomposite materials in wastewater. Furthermore, IR spectra results of treated-wastewater show that residual nanocomposite materials are dispersed in wastewater. However, the residual photocatalysts are not dispersed in the treated-wastewater by using the photocatalytic reactor,which mean that the recycle processes to nanometer photocatalysts are not required anymore for normal wastewater treatment.}