Ring-opening polymerization (ROP) of L-lactide (LLA) was carried out in bulk and toluene solution, respectively, using sodium bis (2-methoxyethoxy) aluminum hydride (Red-Al) as the catalyst (initiator). Experimental results show that Red-Al possesses typical characteristics of a living polymerization initiator. Bulk polymerization (110℃, 48 h) of LLA gives a snowwhite polymer of high isotacticity (≥95.2%), moderate molecular weight (MW) (Mn=2.3×104), and quite narrow MW distribution (MWD, PDI=1.12). Investigation of the kinetics of the polymerization in toluene shows that plots of In ([M]0/[M]t) versus time and Mn (numberaverage MW) of synthesized PLLA versus monomer conversion are linear, which is a typical feature of living polymerization. The mechanism of the ROP was postulated on the basis of 1H NMR monitoring of the polymerization. The synthesized PLLA shows high isotacticity. The degree of transesterification and stereoselectivity of the ROP by Red-Al were estimated according to 13C NMR characterization of poly rac-LA.