Abstract: The flow field has an important effect on the performance of the emitter. So it is significant to study this kind of flow in detail for improving the performace of the emitter. In the paper, the Galerkin penalty finite element method was applied to simulate the flows in the emitter. At different flow rates, the flow characteristics and the influence of the Renoldy numbers on flow field in the arc type labyrinth emitter were analyzed. According to the numerical simulation results, a new formulation for calculating flowing coeffecient and rate of discharge is presented. These valued data provide references for continuous development of emitter.