Poly lactic acid (PLA) is one of the bio-based polymer with biodegradability and excellent rigidity, but has low toughness. There are various methods to solve the poor toughness of PLA such as polymer blending and crystallization. In this study, in order to improve the toughness of PLA, epoxidized natural rubber (ENR) with excellent flexibility was added into PLA, and PLA/ENR blend materials were prepared. But,　This blend materials was incompatibele and greatly reduced mechanical properties. Therefore, in order to improve compatibility between PLA and ENR, a compatibilizer was added into PLA/ENR blend materials. Mechanical properties of blend materials were evaluated using tensile tests and charpy impact tests, and the effects of ENR addition and compatibilizer addition were investigated using SEM and measurement of glass transition temperature. As a result, ENR particles were refined and Tg shifted to the low temperature side by addition of compatibilizer. In the case of compatibilizer was added into PLA/ENR blend materials, mechanical properties was improved in comparison with the case of PLA/ENR blend materials.