With the development of industry, the development and utilization of a large number of natural resources in Inner Mongolia, a large number of industrial solid waste storage caused a series of environmental problems. Using industrial solid waste such as Mineral powder, fly ash and wet carbide slag to prepare geopolymer to replace part of cement for pavement base construction, not only solves the problem of large solid waste consumption, but also protects the environment. In this paper, the strength variation law and strength formation mechanism of mixtures with different geopolymer content were studied by mechanical property test, scanning electron microscope (SEM) and mercury intrusion porosimetry (MIP) test. Meanwhile, based on the grey relation theory, the correlation degree between the indexes of harmful pores, harmful pores and total porosity and the mechanical properties indexes was obtained. The results show that the performance of the mixture is also different with the different content of geopolymer. In the case of 20% geopolymer content, the UCS (unconfined compressive strength) and ITS (indirect tensile strength) at the same age are better than those of the mixture without geopolymer, while the mechanical properties of the mixture with 40% geopolymer content are lower than those of the mixture without geopolymer. The grey relation analysis shows that the UCS and ITS of the mixture under different geopolymer content are mainly affected by the rise of harmful holes, while the CRM (compressive resilient modulus) is not affected by the change of pore size, but decreases with the increase of geopolymer content.