Innovation internationalization of private enterprises is an important force to promote the domestic and international double-loop circulation under the new development pattern. The mode of innovation internationalization of private enterprises is analyzed, and it is divided into two types: outward innovation internationalization and inward innovation internationalization. On this basis, the mechanism of innovation internationalization of private enterprises is analyzed to promote domestic and international double-loop circulation, namely, knowledge transfer and diffusion, organizational learning and ambidexterous synergy. Based on the theory of double-loop springboard, the path of private enterprise innovation internationalization to promote domestic and international double-loop circulation is put forward .