Abstract: Reducing production costs and meeting the requirements of the field engineering are the two main indicators of choosing paste filling material ratio. We adopt orthogonal experimental design method to determine the experiment scheme as the “three factors and five levels”. The three factors are percentage of cement, ash and gangue ratio and paste concentration. We conduct intuitive analysis and variance analysis on the experimental results, and draw the conclusion that the factors that influence early strength are cement volume percent and paste concentration, and factors that influence ultimate strength are the percentage of the cement and ash and gangue ratio. We get optimal ratio of paste concentration through multiple linear regression method and Gauss elimination method. The percentage of cement is 12.705%, ash gangue is 0.400, and paste concentration is 77.498%. Finally, the strength of optimal proportion is tested in laboratory, the test results in the seventh days is 0.93 MPa, and in the twenty-eighth days, the test results is 3.21 MPa, both of which meet the requirements of on-site engineering.