Given the increasing importance of water in agriculture, major investments for the development of pressurized irrigation systems, in particular sprinkler irrigation have been done. In other hand, precision in designing sprinkler irrigation systems is an important factor in reducing runoff. For the purpose of correct designing and preventing of surface runoff, recognizing soil infiltration rate (I) is necessary as the most important parameter in designing irrigation systems. This study was conducted to compare three field methods of measuring the soil infiltration rate, includes double ring (DR), tension infiltrometer(TD) and time of ponding (TP) methods and developing of pedotransfer functions to estimate the soil infiltration rate. Also, the Green-Ampt, Philip, Kostiakov, modified Kostiakov, and Horton and the America's Soil Conservation Service were evaluated. At all five experimental sites were measured four indicators of soil texture, initial moisture, bulk density and organic content percentage in three replicates . The results showed that the infiltration rate has significant correlation with organic content percentage, bulk density, initial soil moisture percentage, and clay and silt percentages. Developed pedotransfer functions had high accuracy in estimating the soil infiltration rate. Also it was observed that the measured I values in the DR method, on average, were 2 - 3 times more than TP method and, 4 - 5 times more than TD method in loamy sand and sandy clay loam textures. The final infiltration rate values of TD method to the suction of 2, 5 and 10 cm, were about 4, 3 and 2 times more than TP method, respectively. Also the final infiltration rate values of DR method were 5 times more than TP method. Saturated hydraulic conductivity values were calculated by TP method on average were 1.5 times more than DR method. Hydraulic conductivity of TP method were 0.7 and 0.4 times more than DR and TD methods in investigated soils, respectively. Our results suggest that the need of adjustment final infiltration values and hydraulic conductivity which werw resulted from double ring and tension infiltrometer methods in designing sprinkler irrigation systems. The highest average correlation coefficients betwee the field data and estimated data were observed for Kostiakov and Horton models and the lowest average correlation coefficient was observed for the America's Soil Conservation Service model. Overall, we concluded that for designing sprinkler irrigation systems in farm scale (over 100 ha), infiltration rate would be measured by the time of ponding method However, in the field scale (lower than 100 ha) it can be measured by double ring and tension infiltrometer methods then, infiltration rate values have to adjust by be developed equations. Keywords: Infiltration, Double ring, Tension infiltrometer, Time of ponding, Pedotransfer functions, Infiltration equations