Amid changes in the business environment and increased competition, sustainable innovation has become the key for new ventures to survive and develop. Innovation capability is considered to be closely related to entrepreneurial orientation and organizational learning. However, there was no in-depth analysis of sustainable innovation capability from an ambidextrous perspective to distinguish from traditional single-episode innovation and no systematic empirical study to explore the internal relationship among the three factors mentioned above in a new venture scenario. Employing the ambidextrous perspective, this paper explored the impact of entrepreneurial orientation on the sustainable innovation capabilities of new ventures and examined the mediating effect of ambidextrous learning. Using the multisource data of 279 new ventures from China, this paper empirically tested the research hypothesis. The results showed that: (1) The three dimensions of entrepreneurial orientation have a significant positive impact on the sustainable innovation capability of new ventures; (2) Ambidextrous learning partially mediates the relationship between entrepreneurial orientation and the sustainable innovation capability of new ventures; (3) Both the equilibrium and interaction effects of ambidextrous learning positively affect the sustainable innovation capability of new ventures. This study clarified the relationship between entrepreneurial orientation and the sustainable innovation capability of new ventures, emphasized the equilibrium and interaction in ambidextrous learning, and provided theoretical support for new ventures to form and develop sustainable innovation capability.