Non-depositing critical velocity is an important parameter in project design for low pressure pipe irrigation system in irrigation districts of sediment-laden water resource. The velocity used to be calculated through the critical velocity equation for solid particles delivery in pipeline system. However, the calculation error is relatively large due to the small sediment content and the large fine-textured particle content. This paper conducted different non-depositing critical velocity experiments under 6 sediment concentrations and 4 pipe diameters. The impacts of sediment concentration, pipe diameter, particle size and distribution on the non-depositing critical velocity of water delivery in pipeline system were analyzed based on the experimental results.