Oil produced from offshore reservoirs is usuallymixed with sand particles. Sand particles in slurry flows impact pipeline walls and cause erosion damage. Therefore predicting the erosion rate is very crucial in oil industries. In order to gain a better understanding of the effect of sand concentration on the erosive slurry flows a series of submerged impinging jet tests was performed. Total erosion ratio was calculated by measuring the weight loss and the thickness loss of the eroded coupon was also measured using a 3D profilometry scan. It is found that the erosion ratio does not change significantly with increasing the sand concentration up to a certain point and then erosion ratio decreases. This observation can be ascribed to particle-particle interaction and more sand particle rebounds near the surface at higher concentrations which can protect the target surface from more particle impacts. Also the effect of particle-particle and particle-flow interaction on erosion ratio in various concentrations is studiedby Computational Fluid Dynamics (CFD) simulation.