Pressure manifold is prone to failure caused by cuttings and gravels included in the underground natural gas and shale gas. In particular, the tee tubes are one of the most easily failed components. In order to study the erosion wear mechanism of tee tubes. T-tube, Y-tube, and y-tube pressure manifolds are systematically studied. The results show that structure and gas inlet affect the tube's field distribution and erosion. After gas shunts (separated flow), high-pressure areas are concentrated on junction and downstream, while high-pressure areas are concentrated downstream after the gas conflates (sink flow). Erosion area and particle trajectory of the tee tubes under the effect of shunting and confluence are analyzed. Overall erosion of Y-tube is the most severe. Taking erosion wear degree into account, y-tube is a better choice.