In order to remove indoor formaldehyde (HCHO) efficiently and cheaply, two kinds of novel amino functionalized diatomite (DE) modified by 3-aminopropyltriethoxysilane (APTS) and glycine (GLY) (i.e. APTS/DE and GLY/DE) were successfully synthesized by wetting chemical method. First, the optimal preparation conditions of the two kinds of amino modified diatomite were determined, and then their microstructure and morphologies were characterized and analyzed. For comparation, a series of batch HCHO adsorption experiments of the two kinds of amino modified diatomite were conducted. According to the experimental results, the pseudo-second-order kinetic model and the Langmuir isotherm model could well describe the adsorption processes, and the maximum adsorption capacity of APTS/DE and GLY/DE prepared under the optimized conditions at 20 ℃ were 5.83 and 1.14 mg·g-1, respectively. In addition, the thermodynamic parameters indicated that the adsorption process is a spontaneous and exothermic process. Overall, the abundant amine groups grafting on the surface of diatomite was derived from Schiff base reaction, which is essential for high-efficient adsorption performance toward HCHO.