Abstract:The current high pressure manifold pipe erosion wear theories are all lacking considerations of the effect caused by high pressure load. The characters of high pressure pipe manifold erosion wear were analyzed. The result shows that the band is facing the internal pressure, the generated circumferential stress which is also named tensile stress, is larger than the longitudinal stress. Experiment of erosion wear for high pressure pipe manifold material 40CrMo was carried out with the self developed equipment which can provide tensile stress to the sample. According to the experiment result, it is found that along with the tensile stress increasing, the erosion wear of 40CrMo is increased, and the resistance to the erosion wear of material is decreased.