Abstract: The compatibility of the insitu composite of Polycarbonate(PC) and liquid crystalline copolyester can be improved by adding the multiblock copolymer prepared from PC and LC copolyesteramide oligomer. The mechanical properties of blends are increased when increasing the adding amount of block copolymer. Through the observation of SEM it can be found that the deformation of LC particles can be improved by the block copolymer and the interfacial adhesive becomes better.