Abstract: This paper introduced the primary organic modification andsecondary organic modification of montmorillonite (MMT), and the applications of modified MMT in poly(lactic acid) (PLA) were highlighted. A number of studies indicated that the secondary modification could effectively improve the dispersion of organically modified MMT (OMMT) in the PLA matrix and alsomake it possible to form an exfoliation structure. The addition of OMMT could also effectively enhance the crystallization performance, tensile modulus, impact strength, thermal stability, barrier properties and rheological behavior of PLA.