The mechanical properties of geopolymer samples synthesized by nine kinds of metakaolin under different cuing temperatures were investigated, and microcalorimetry, infrared spectrum(FTIR) and SEM EDS were employed to study the mechanism of influence of curing temperature on the geopolymer performance. Test results show that increasing curing temperature can promote dissolution and polycondensation of aluminosilicate and thus enhance the mechanical properties of the obtained geopolymer. However, too high curing temperature leads to too fast polymerization, thus the dissolution products will be enclosed by gel generated by polymerization before they can involve in the subsequent reactivity. That results in an uncompleted polymerization reaction and a decrease of compressive strength of geopolymer.