Subsurface drip irrigation(SDI) is one of effective irrigation methods. But it is easy to clog. It is the key problem of the SDI system whether emitters are clogged. An investigation of emitter clogging was conducted in a SDI system, which had been running for 8 years. Clogging rates of Labyrinth emitter, mini-pipe and orifice reached 16.67%, 25% and 63.89%, respectively. These clogging were mainly caused by attached granule. Some sugestions were put forward was to solve this problem, such as enhancing filtration, flushing timely and improving the route of water in the emitter.