To extend the potential applications of polylactide (PLA) in film blowing, foaming, thermal molding, and so on, the high-viscosity PLA composites with various compositions of carboxyl-ended polyester (CP) and solid epoxy (SE) have been successfully prepared by an in situ reaction blending process. Their rheological properties, crystallization behaviors, tensile properties, and morphologies have been investigated in detail. The results show that the complex viscosity eta*, G', and G'' at low-frequency region and the tensile strength of PLA composites are obviously improved with the addition of CP/SE, but the nonisothermal crystallization of PLA component is hindered. SEM reveals that some microphase separations existed in the as-prepared composites. (c) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012