Water purification from radionuclides by using an effective and low-cost adsorbent which it is produced in high quantities from the fuel combustion in power stations where mazote, coal and other fuels extensively used. Fly ash's particles were used to investigate the removal of uranium238 ions, in the concentration range of 27.9, 55.8, 111.6 Bq/l from ground water. In order to research the effect of various parameters including pH, contact time, initial metal ion concentration, dose adsorbent and temperatures batch tests have been performed in adsorption. The optimum contact time was 30 minutes and the appropriate pH was found to be 4.5. Temperature effects on kinetics and equilibrium were closely investigated in fly ash spores. Endothermic findings and a temperature rise resulted in an increase in the adsorption rate of uranium239. Data was applied to different temperatures (293, 303 and 313 K) with the isotherms Langmuir, Freundlich and Dubinin – Radushkevich. The best way to explain the data was to find the Langmuir Adsorption Model. Adsorption kinetics have been studied in pseudo-first, pseudo-second order. A pseudo-second-order mechanism was the best in fitting the data. Thermodynamic parameters; ΔH°, ΔG°, and ΔS° have been studied. SEM is used to assess morphological changed in the fly ash surfaces following adsorption of uranium238 ions.