Due to the importance of the preparation of nanomaterials and the control of the size and forms of their structures and the application of the applied value of these materials to these two factors, a device and a reactor for the production of nanomaterials was designed and converted in a wet thermal manner. The reactor, made of stainless steel, lined with Teflon, is resistant to chemicals and has a temperature range of 300 ° C. It contains a heat element connected to a self-controlled control circuit through an external control box with a accuracy of ± 1 ° C . This device was tested in the preparation of nanomaterials starting from a micron size materials. Nanomaterials were also converted one shape  to another and the nanoparticles, nanotubes of  ZnO and TiO2 were listed as examples. The  preparation performance of the device was examined using by testing the products using scanning electron microscopy (SEM) where it showed the sizes, shapes and morphologies of the materials produced in this device.