Abstract: Magnesium hydroxide has the advantages of buffering, great activity and strong capacity, and therefore, has attracted more attention than other strong alkalis. With the increase of people's consciousness of environment protection, innocuous, highly effective and smoke-depressing inorganic flame retardants, especially magnesium hydroxide flame retardant, have been attached great importance to. The paper reviews the status quo of the research on the preparation of both foreign and domestic nanometer magnesium hydroxide and presents in detail the preparation methods including direct precipitation, hydrothermal reaction, precipitation-azeotropic distillation, pulsed-laser ablation, reversed precipitation, microwave-assisted synthesis, liquid-solid arc discharge, surfactant-induced solution, supergravity technology and normal temperature solid phase.

Key words: Nanometer magnesium hydroxide, Direct precipitation method, Hydrothermal reaction method