Magnesium hydroxide sulfate hydrate (5 Mg(OH)2·MgSO4·3H2O abbreviated 513MHSH) whiskers using for fiber reinforcements and fillers are synthesized via a reflux reaction by using MgO and H2SO4 as reactants. In general, the 513MHSH whiskers have hydrophilic surface and heat resistant property with crystal water molecules. In this work, surface modification and SiO2 coating technique were employed for various application by coating with organic and silica layer on 513MHSH whisker surface. Also, SiO2 coating system is important for preventing aggregation and enhancing thermal stability [J Kor Ceram Soc 55:618, 2018; J Nanosci Nanotechnol 10:380, 2010]. Controlling pH value acts as important factor for establish one-step process that synthesis and surface modification/SiO2 coating process simultaneously to improve the efficiency in terms of the time and process. The morphology and phase of synthesized 513MHSH whiskers are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Surface modified whiskers were characterized by Fourier transform infrared spectroscopy (FTIR) and the thermal stability of SiO2 coated whiskers were evaluated by thermogravimetric analysis (TGA).