This paper studies the bulk-melting blend behavior of L-PLA/PCL and their transesterification. The degration of two polymers is apparently observed in blend with catalyst titanium (IV) tetrabutoxide Ti (OBu)₄ at 150 C. The presence of significant transesterification is proved by ¹³C-NMR spectroscopy and differential scanning calorimetry (DSC) in blend of L-PLA/PCL. The average lengths of lactone block Lc and of L-lactide block L1-in the copolymer are calculated from ¹³C-NMR spectra and their molar composition are derived from ¹H-NMR spactra.