Mg- Al layered double hydroxide ( LDH) was modified with sodium dodecyl sulfate ( SDS) by regen-eration method． Polyethylene /modified LDH composites ( PE /SDS- LDH) were prepared by melt blending and solu-tion mixing method． Maleated polyethylene ( PEgMA) was used to improve the compatibility between LDH and PE．The structure and dispersion of LDHs in PE matrix were investigated by X- ray diffraction ( XＲD) and scanning e-lectron microscope ( SEM) ，respectively． Thermal degradation behaviors of PE /SDS- LDH composites were charac-terized by thermogravimetric analysis ( TGA) ． The results reveal that microcomposites ( PE /PEgMA/SDS- LDH)were obtained by melt blending method and nanocomposites ( PE / ( PEgMA/SDS- LDH) ) were prepared by meltblending PE with master- batch of SDS- LDH and PEgMA obtained by solution mixing． Due to the thermal decompo-sition of LDHs at much lower temperature than PE，thermal degradation of composites begins at low temperature re-gardless of the dispersion of LDH in PE． However，nanocomposites present better thermal stability． Compared withmicrocomposites，the nanocomposites present the higher peak temperature and more residues at the end of thermaldegradation，indicating the better barrier properties and charring effects of nano- dispersed LDH．