Rheological curves of pig manure with different solid holdup and temperatures were measured by a rotational viscometer. The effects of solid holdup and temperatures on the rheological behaviors were studied. The results indicated that pig manure behaved like pseudoplastic fluid and followed the power law model. The apparent viscosity showed an “upward growth” trend with the increase of solid holdup, but the temperature had little influence on it. There were some critical points on viscosity and solid curves, and they could be used as the standard of non-Newtonian fluid (pig manure) regarded as Newtonian approximately. There were also some critical D values on viscosity and shear rate curves, proposing that they could be used as definition of dead zone. The mechanism for temperature affecting apparent viscosity was discussed. Finally, the relationship between analyzed apparent viscosity and solid holdup and shear rate with the help of multiple nonlinear regression were analyzed, and a mathematical model was established and fittted well with experimental results, which provided the relationship of physical parameters in the functional form for process design and optimization involving non-Newtonian fluid (pig manure).