The process of sand-wall collision was performed to analyze the relationship between the collision and clogging of labyrinth channel emitter. First, the effect of Rc on pass rate of sand was analyzed using the CFD method. It was found that Rc has a great impact on the anti-clogging characteristics of labyrinth emitter and should be determined through experiments. In order to provide the experimental basis for the setting of sand Rc in numerical simulation, experiments of PTV were carried out for the determination of Rc under various pressure and different structure of labyrinth channel emitter, so that the anti-blocking performance can be more accurately evaluated.