In this work, various backbone binders were used in wax-based binder system to formulate zirconia parts by ceramic injection molding (CIM). The effect of different backbone binders on the molding, debinding, and sintering behaviors was investigated. After blending process, the feedstock using multi-polymer components exhibited more homogeneous structure compared with that using the mono-polymer ones due to the synergistic effect of multi-polymers. During solvent debinding, some defects such as “slumping” and “peeling” appeared in the parts containing ethylene-vinyl acetate copolymer (EVA), but they were not found in the parts with other thermal polymers. Also, as for the parts after sintering, the one using low density polyethylene (LDPE) and high density polyethylene (HDPE) as backbone binders presented a more uniform microstructure with finer zirconia grains among all the investigated compositions, and thus obtained the highest flexural strength (~949 MPa) and relative density (~98.9%).