In the present study, slurry erosion experiments of stainless steel SUS-304 were carried out using new advanced erosion test rig, where the multiphase flows of alumina sand and water were utilized as the erodents. The results show that erosion rate was initially high and gradually reduced over the testing time. In addition, the erosion rate increased with an increase in impact velocity. The surface roughness increased with either increasing testing time or impact velocity. Further, the surface profiles of "W" shape were observed for all eroded samples. Microstructural characterization reveals two different erosion regimes: plastic deformation mechanism dominated at high impact angles, while plowing/cutting mechanism dominated at low impact angles. A correlation between the erosion rate, erosion profile and microstructure is also discussed.