The　nanostructured　Mg3Si4O10(OH)(2)　in　situ　grown　on　diatomite　were　first　synthesized　via　a　hydrothermal　route.　Moreover,　Mg(OH)(2)　nanoflowers　were　first　grown　on　the　surface　of　diatomite　after　hydrothermal　treatment　for　0.5　similar　to　2　h,　these　nanoflowers　obtained　the　surface　areas　of　180　m(2).g(-1).　As　the　hydrothermal　reaction　time　increasing　to　3　h,　the　Mg　(OH)(2)　nanoflowers　were　completely　transformed　to　lattice-like　structure　Mg3Si4O10(OH)(2)　which　possessed　the　higher　surface　area　of　350　m(2.)g-(1.)　Mg3Si4O10(OH)(2)/diatomite　composite　structure　showed　a　well　adsorption　performance　of　570　mg　＂g-＇　for　Cr(VI).　It　is　firmly　believed　that　the　adsorbent　has　a　great　significance　of　removing　heavy　metal　ions　in　wastewater.