Polylactideacid (PLA) is a biodegradable polyester obtained by synthesis of lactic acid, which can be produced from renewable. With good biodegradability and good processability, PLA was regarded as one of the most biodegradable polymers and was expected to substitute of the nonbiodegradable plastics. The poor heat and mechanical properties limited its applications. Many technologies, such as crosslinking structures were proved effective for enhancing the heat stability or mechanical properties of PLA materials. The crosslinking structures of PLA can be formed by irradiation. Chemical crosslinking is another possible way to introduce crosslinking structures in PLA. Some chemical reactions between the crosslinking agent and the polymer chains can be initiated by chemical treatments, and modified PLA materials with different gel fraction and crosslinking density for further processing of PLA products can be obtained. For example, peroxide crosslinking of PLA with dicumyl peroxide (DCP) can form a gel structure. The high peroxide concentrations resulted in a steep drop of the tensile strength. In addition, a large amount of chloroform solvent was required, and a further separate purification step was necessary. In this research efforts on the chemical crosslinking of a commercial PLA aiming at improving the thermal stability and mechanical properties. This method is economically advantageous because it was carried out in the melt state with only low amounts of TAIC and DCP, and no extra purification step and special apparatus were necessary. Keywords: PLA, Crosslink, Network, Property, Behavior