Fly ash based geopolymer were prepared with fly ash as raw material and several compounds of heavy metals as additives. Then the effect of the type, content and chemical form of the heavy metal on the compressive strength, reaction products, and pore structure of the prepared geopolymers was investigated. The results show that the incorporation of Pb²⁺、Cr³⁺ and Cu²⁺ has great effect on the late compressive strength and results in formation of reinhardbraunsite in the solidified body. Moreover, the Pb²⁺ reduces the total pore volume of the solidified body, while Cr³⁺ and Cu²⁺ increase it. The content of the heavy metal compounds should be controlled within a reasonable range. When the content of the heavy metal compounds is relatively small, the total pore volume is small and the solidified body is much compact. Besides, the different chemical forms of chromium have different effect on the stability of the geopolymers. The single addition of chromium oxide or elemental Cr may reduce the total pore volume of the geopolymers, whereas the average pore size increases obviously for the geopolymers with addition of a variety of other heavy metal compounds.