Abstract: A subirrigation porous pipe was tested in laboratory using distilled water. Results show that the emission rates of the pipe decline with time first and then reach a relative stable value. In the range of pressure from 0 to 7.0 mH₂O, the emission rates expose a power function with the operating pressure. The emission uniformity of the pipe also varies with pressure. Compared with the results using distilled water, applying tap water in the tests leads to decrease in both emission rates and emission uniformity, while pressurization helps to weaken clogging in the pipes. The study indicates that the effect of operating pressure on discharge characteristics of the subirrigation porous pipe is remarkable, and the emission uniformity of the pipe is in need of improvement.