Nanocrystalline europium-doped tine oxide (SnO2: Eu) were synthesized by a polyacrylamide gel method. The effects of heat treatment on structure, grain size and luminescence properties of SnO2: Eu were studied with X-ray powder diffraction, transmission electron microscopy and photoluminescence measurements. The results indicate that high heat treatments can enhance greatly luminescence intensity of the samples. Furthermore, the presence of carbon network/cages in the polyacrylamide gel can effectively prevent particles agglomeration,so even when sintered at higher temperatures (1000℃), the grain size is still below 20 nm.