Pulp rheology is an important factor affecting flotation. The effects of particle size (150-74 μm, 74-38 μm, 38-23 μm, -23 μm), pulp density (11.76%-34.78%), pH (5.3-12.4), collector concentration (25-500 mg/dm3), and stirring intensity (400-900 rpm) on the rheology of smithsonite, kaolinite, quartz, and calcite minerals were investigated in detail. Additionally, the agglomerate morphology of particles was observed by a polarizing microscope. The results showed that as the mineral particle size decreased and pulp density increased, the apparent viscosity and yield stress of the pulp increased. Especially the fine mineral particles (-23 μm) presented a higher apparent viscosity and yield stress. The order of apparent viscosity and yield stress for the minerals from large to small was: kaolinite>calcite>smithsonite>quartz under different pH values, the collector concentrations, and stirring intensities. In the presence of collector of octadecylamine, smithsonite, kaolinite, and calcite particles could form aggregates, especially smithsonite particles presented obvious agglomeration with large particle size and compact network structure. The agglomeration effect of calcite and kaolinite particles were weaker than that of smithsonite. The particle agglomeration resulted in the increase of the apparent viscosity and yield stress of the pulp. Quartz particles did not form clusters，hence the pulp’s apparent viscosity and yield stress were the lowest. The research on the changes in rheological properties of the pulp will hopefully provide some guidance for future flotation.