A novel layered double hydroxide/NaSb(OH) 6 -based nanocomposite (Sb-LDH) has been prepared via intercalation of thio-antimonite (SbS 3 3À ) and reconstruction of LDH using Mg-Al LDH as precursors. It is composed of LDH nanolayers with thickness of 25 nm and NaSb(OH) 6 nanoparticles with diameter of 3-25 nm. The presence of NaSb(OH) 6 will decrease the decomposition intensity and hinder the decomposition of Mg-Al LDH because of the potential synergetic effect. When applied to poly(vinyl chloride) (PVC) composites, both Mg-Al LDH and Sb-LDH can enhance the thermal stability and increase the decomposition temperature of PVC. Compared with Mg-Al LDH, Sb-LDH results in higher decomposition temperatures and whiteness and higher initial and long-term stabilities due to the pres-ence of NaSb(OH) 6 , which can react with HCl and coordinate with Cl in the PVC chains. Because Mg-Al LDH will accelerate the dehydrochlorination of PVC driving by the Lewis acid such as AlCl 3 , the thermal stability of PVC decreases with increasing nanofiller loading. When 1 wt % Sb-LDH was added, the color change time and Congo red time of PVC composites are 140 min and 154 min, respectively. With enhanced thermal stabilization, this novel LDH nanocomposite could gain promising application in thermal stabilizer for PVC resins. V