Biodegradable polyesters with free hydroxyl groups were synthesis by the lipase-catalyzed polycondensation of L-malic acid with different diacids (succinic acid, adipic acid and sebacic acid) and diols (ethandiol, 1,4-butanediol, 1,6-hexanediol and 1,8-octanediol). The molecular weight (Mw) of the copolymers was affected by the alkylene chain lengths of diacids and diols. It was found that diacids and diols with longer alkylene chain lengths have a higher reactivity than that of shorter chain-length diacids and diols. The crytallizability of the copolymers were affected by the alkylene chains length of diacids and diols. The crytallizability decreased with the decreasing of the alkylene chains length of diacids and diols.