he systematical analyses on the rheological concepts and principles concerning the powder injection molding (PIM) process are carried out. The creeping regularities and the flowing rate distributions at the flow front in the cylinder cavity on the Newton flow, Power-law flow and Bingham flow, which are of great importance in PIM, are derived. Finaly, the rheological analysis in St3N4-binder injection molding system is discussed as an example of rheological principles and their application.