We report based of the new concept for controlling crystal polymorphs of CaCO3, entitled "latent inductor method", [10] the results obtained by developing the crystallization in the same time with polymerizations process of methyl methacrylate. The crystalline form of product is discussed reported to analytical results obtained by FT-IR spectroscopy, X-ray, SEM. We discuss, in the same time, the particularity of polymeric assistant of crystallization process.