The PLA/PAE blends with four different weight ratios were prepared by melt mixing. PLA and PAE in PLA/PAE blends were almost immiscible while the weak interaction between PLA and PAE existed. The sub-micrometer PAE domains were dispersed in PLA matrix uniformly. The physical aging of PLA could be inhibited by introducing PAE. For PLA/PAE, the structure formed by physical aging at room temperature induced the accelerated crystallization of PLA during heating. However, for neat PLA, the structure formed by physical aging had a negligible effect on the crystallization of PLA during heating. The isothermal crystallization kinetics of neat PLA and PLA/PAE were analyzed by Avrami theory. The values of Avrami exponent were within the range 2.1-3.0. The crystallization rate of PLA was enhanced significantly by addition of PAE.