[en] Korea institute of nuclear safety has operated monitoring system(Ion chamber, Scintillation detector, Thermoluminescence Dosimeter). Gamma exposure rate dependent on regional environment, season and diurnal(daily) variation, meteorological factor etc. There are many variable so that analysis of gamma exposure rate is too complicated. This paper confirmed diurnal variation and analyzed relation radionuclides in the soil and gamma exposure rate. For 10 monitoring locations, we compared diurnal(daily) variation of gamma exposure rate measured by monitoring ion chambers with the concentrations of radionuclides of the soils nearby the ion chambers. Using the data provided by IERNet, the gamma exposure rates are analyzed into four types. The concentrations of radioisotopes of the soil nearby 10 monitoring locations are obtained using a HPGe detector system