To explore relationships between uniformity coefficient and distribution coefficient, the fluidic sprinkler with circular outlet cover plate (OCP) was chosen as the object. Five different OCP diameters were designed. The sprinkler cannot rotate when the diameter was less than 5.0 mm or more than 7.0 mm. Experiments were carried out under the operating pressure of 200 kPa, 250 kPa and 300 kPa and the radial water distribution of 5.5 mm, 6.0 mm and 6.5 mm, respectively. Square layout and combination spacing with 7～15 m were chosen. CU and DU were calculated by using the method of interpolation. The results showed that for the circular OCP, more water was distributed near the sprinkler with the increasing operating pressure. The optimal OCP diameter was 6.0mm. Combination of CU and DU was slightly influenced by the operating pressure. As well as the increasing of the combination spacing, CU variation was stable firstly but sharply decreased later, and DU variation experienced three processes of becoming lower, becoming higher to attach the maximum value and becoming lower again for the reason of leakage spraying. The formula between CU and DU was put forward which was hoped to be a theoretical foundation for the project.