Abstarct: Gamma rays mainly interact with the matter through three ways: photoelectric, Compton and pair production interactions that finally lead to absorbing and scattering rays from the material. Therefore in this study two methods of attenuation gamma rays and back scattering of the soil surface is used for the measuring of the moisture. Attenuation and scattering of gamma rays in the soil depend on beam energy, density and thickness in soil. If radiation energy an soil thickness don't change, main factor in attenuation an back scattering in the soil will be its thickness; and density depend on soil moisture. Then we can measure moisture from attenuating an back scattering gamma rays from soil. MCNP-4C is multipurpose code that can be used for neutron, photon, electron transport. In this code all the gamma rays interactions with matter, such as coherent and incoherent scattering and absorption processes are simulated with the monte carlo modeling. In this work, first, with the monte carlo simulation was obtained the optimum situation for moisture measuring, and then was done related experiments. In the measuring of the moisture with the attenuation, primarily, is simulating for some energies and moistures. After gaining good results, is performed same modeling for real sources in laboratory. Thereupon 60Co is selected as the best source for experiments. Finally affection of the container soil was studied in attenuation soil. In modulating through back scatter method with simulating, first, 241Am is elected as the optimum source. In this process was introduced a quantity, is known contrast. And was saw that with the growing the moisture, contrast is increased linearly. Therefore we can use this was for moisture measuring. Also, it was gotten the optimum source and detector distance from soil with monte carlo modeling. Then with this results made related experiments. Finally, there were a good matching between monte carlo simulation and experiments.