Further densification, and even full densification of the ceramics, could only be achieved by post-annealing at very a low temperature [18,23]. Therefore, the combination of nanopowder, CSP, and post-annealing is expected to easily prepare dense ceramics with the desired grain size with a low energy cost. The preparation of Li2Mg3TiO6 nanocrystalline ceramics proposed here outlines an approach that employs the CSP method.