This work is motivated by current researches in the development of PLA applications as a biodegradable polymer. In this study, a new compatibilizer based on maleic anhydride grafted polyethylene glycol grafted starch (mPEG-g-St) was synthesizedto improve the compatibility of the poly(lactic acid)/thermoplasticstarch blends. To study the efficiency of synthesized compatibilizer,several blends samples were prepared based on PLA/thermoplasticstarch and their morphology, dynamic-mechanical behavior,crystallization, mechanical properties and biodegradability werestudied. Following results can be drawn from this work: