Abstract: Three steps, the drying, calcining and reducing-sintering of wet gel spheresin heat-treatment of gel-supported process for preparing dense UO_2 microspheresare studied. The influences of the ways of drying, temperature of calcination,O/U ratio of the intermediate products, temperature of reducing-sintering, andthe rate of temperature elevation on the end-products are analysed. The parame-ters for UO_2 microspheres densification are optimized. The density of UO_2 micro-spheres is upto 95% T. D.