To insure the construction and running of slurries transportation pipeline be economical, the annualized conversion total cost model of slurries transportation pipeline was set up. Considering the impact of slurries concentration and slurries convey velocity on total cost of slurries transportation pipeline, these two parameters were chosen to be variables for optimizing. In view of the complex nonlinear of the model, the parallel global search ability of combined GA-DE (genetic algorithm-differential evolution) algorithm was utilized to optimize the design parameters of slurries transportation pipeline, the result of which was proved effective. Then this method was applied to a sludge treatment plant for final disposal in Changchun City. The optimization results showed that the optimum slurries concentration was 2.32％, the transportation velocity was 1.10 m／s, the diameter of the pipeline was 300 mm, and the annualized conversion total cost was 528.3 thousand Yuan RMB under the condition of flow rate of 0.226-0.045 m³／s (slurries concentration varying from 0.8％ to 4.0％) and the transportation distance of 4.5 kilometers.