Abstract: There are seven typical non-Newtonian rheological models. Significant level of these models was analyzed by combining with sludge in order to establish the relative optimal model. The rheological experiments of sludge with moisture content in the range of 93.99%-98.72% were carried out at 20℃ by using a rotating viscosity meter, and sludge rheological characteristics were analyzed. The seven rheological models were fitted with the experimental results and white noise test was carried out to verify the effectiveness. Results display that the moisture content has bigger effect on the viscosity of sludge at the low shear rate of 0-150s ^-1. The apparent viscosity is below 0.5Pa·s when the sludge is in the range of moisture contents of 96.31%-98.72%, which is suitable for long-distance transportation. While the sludge in the range of moisture contents of 96.31%-98.72% is not suitable for long-distance transportation as it has higher apparent viscosity. The significance level of Power-law model is better than the other two parameter models when the moisture contents are among 93.99%-95.52%. When the moisture contents are among 93.99%-98.72%, the Sisko one is better than the H-B among the three parameter models, the Carreau model is better than the Cross among the four parameter models.