Abstract: Organic---attapulgite (OAT) was obtained by pretreating attapulgite, then the nano---OAT/polyactide (PLA)-x ( x=1wt%、 3wt%、 5wt%) composites were prepared respectively by in situ polymerization. The composites were characterized by infrared absorption spectroscopy (IR), scanning electronic microscope (SEM) and X-Ray diffraction (XRD). SEM results show equably uniform dispersion and good interfacial compatibility between PLA and OAT. The mechanical capability and thermal analysis (TGA  ＆ DSC) of the composies were measured. Compared with the pure PLA, the tensile strength and elastic modulus of the OAT/PLA3 are improved  by 98.6% and 130.0% respectively. The thermal stability of composites is markedly improved. It also shows that the degradation velocity of OAT/PLA-x is obviously speeded up.