Based on the physical foaming method, precast foams with different properties and pore structure parameters were prepared, and their migration law in the geopolymer paste over time and space was investigated. Then the pore structure formation mechanism of geopolymer foam concrete(GFC) was explored. Furthermore, the relationship between the precast foam with different pore structure parameters and the GFC macroscopic properties was established. In addition, the microscopic morphology of GFC internal pore structure with different precast foam ratios was observed by scanning electron microscopy(SEM).The results show that precast foam with different properties and pore structure parameters undergo different migration processes inside the geopolymer paste, which affects the properties and pore formation process of GFC.