Abstract: This paper explores the effects of different triangular inner tooth top angles on the hydraulic performance and anti-blocking performance of emitters of labyrinth passage. Through FLUENT numerical simulation, the triangular inner tooth structure with the triangular inner tooth top angles of -66.37°, -63.64°, -58.86 °, -53.13°, 63.64°, 66.37° (with 60°as the boundary, positive clockwise and negative counterclockwise) is added to the trapezoidal labyrinth channels to study the characteristics of the flow speed within the channels and the causes of the blockages. Results show there are relatively a few low speed areas with a tooth top angle of 58.86°, 63.64° and 66.37° whereas the vortex area is relatively large and properly positioned when the inner tooth top angle reaches 60°, 63.64° and 66.37°. An analysis of the motion of particles with different sizes in the channel reveals even if the particles in the channel have vortex turnover motion, the retention time is relatively short and the migration trajectory is relatively shorter when the tooth top angle of the triangle is 53.13°, 58.86° and 63.64°. Thus, the anti-clogging performance of the channel improves significantly. The triangular tooth top angle has different effects on the hydraulic performance and anti-clogging performance of the labyrinth passage with inner teeth. The triangular inner tooth top angles have varied impacts on the hydraulic performance and anti-blocking performance of labyrinth passage with inner teeth. With a tooth top angle of 63.64°, the flow velocity characteristics in the labyrinth channels are superior and the sediment clogging is least likely to occur.