A series of different layers ultrathin antioxidant intercalated layered double hydroxides (nL-LDHs, n = 1 to 10) were fabricated in a simple separate nucleation and aging steps route, and the anti-aging performance of nL-LDH/polypropylene (PP) composites was carefully investigated. With the increase of Mg2+concentration from 0.01 mol/L to 0.3 mol/L, the corresponding thickness of nL-LDHs was varied from 2.58 nm to 26.7 nm related to the layer number from n = 1 to n = 10, and the radical-scavenging activity of nL-LDHs was reduced from 51.5 % to 30.2 %. The ultrathin nL-LDHs antioxidants were well dispersed in PP to produce nL-LDH/PP composites with a mass loading of 0.4 wt% via a solvent mixing method. The nL-LDHs antioxidants as a multifunctional agent influence crystallization behavior of PP, and enhance anti-aging performance of nL-LDHs/PP composites. 3L-LDH exhibited the best anti-aging performance and appreciate anti-migration resistance for nL-LDHs/PP composites, which is better than commercial Irganox 1010.