Abstract: The assembled minerals of zirconolite-based doped cerium were synthesized by solid-reaction, using zircon, calcium carbonate, titanium dioxide, alumina and oxalic-acid cerium as raw materials. The preparation of assembled minerals and solidifying cerium in it were researched by means of XRD, BSE, EDS and so on. The results indicate that the better synthesis temperature of the assembled titanate minerals of zirconolite-based doped cerium is 1 230 ℃. The main crystal phase is zirconolite, the secondary phases are sphene and perovskite. The maximum solidifying content of cerium dioxide is 21.39% in the assembled minerals. The mechanism of solidifying cerium in assembled minerals is comparatively complex. Ce⁴⁺ replaces the lattice site of Ca²⁺ or Zr⁴⁺, and Al³⁺ replaces the lattice site of Ti⁴⁺ as an electro-valence compensation of Ce⁴⁺ replacing Ca²⁺ lattice site.