Abstract: The present invention relates to a process for the synthesis of melamine cyanurate in lamellar crystalline shape with high purity and flowability. The procedures include that 1) melamine and cyanuric acid react to form mixture solution, 2) the mixture solution is filter-pressed to prepare filter cake, 3) filter cake and silicon oil are mixed to obtain semi-finished product, 4) dried the semi-finished product until the water content is less than 1.0%, 5) heat the temperature and control certain vacuum degree for curing and crystallizing, 6) the product is obtained. The processing steps of present invention are easy to operate, the processing parameters are easy to control, the production time of melamine cyanurate is short, the quantity of pure water is low, and utilization of equipments is high. Removing the incompletely reacted raw materials and impurities by filter-pressing, greatly increases the purity of semi-products.