Abstract: Heat-treatment of aquamarines from Altay, Xinjiang, has been studied. The shapes of the inclusions in the aquamarine before heat treatment are compared with the ones after heat treatment and the results provide the theoretic bases of enhancement and identification of aquamarines. The research shows that heat-treatment affects the shapes of inclusions. Though the light yellowish green of aquamarine will change into aquamarine-blue under a reduced atomosphere, followed by dark flecks. By means of electron probe, it is further proved that the black flecks are carbon which formed by decomposation of CO in fluid inclusion in aquamarine.