Spin-off，as an organizational change process in which parent company derive startups，is a long-term and holistic development strategy for incumbents. In today's dynamic and complex environment，whether incumbents can achieve innovation ambidexterity through spin-off is the key to ensuring their survival and sustainable development. Based on the "opportunity-motivation-ability" theoretical framework，this paper applied the QCA method to unveil the paths for incumbents to achieve innovation ambidexterity in the spin-off process. It was found that the six factors influencing the achievement of innovation ambidexterity of incumbents are the conjoint effects among six antecedents including policy and market opportunities，motivations of diversification strategy and organizational change，and abilities of resource acquisition and networking. Among these conditions，the strength of incumbents' abilities is the core condition for achieving innovation ambidexterity. When this condition is combined with other related conditions，there emerges the three paths for incumbents to achieve the one goal： innovation ambidexterity. One is the path with multiple equilibrium，in which incumbents actively lay out and fully utilize their abilities in the face of abundant external market opportunities. The second is the ability-driven path，in which incumbents rely on their strong ability endowments when the external opportunities are scarce. And the third is the opportunity-seizing path，in which incumbents seize opportunities by focusing on their main business and utilizing their own abilities when both policy and market opportunities are abundant. However，when the incumbents have weak abilities，even if they have strong motivations for diversification strategy and organizational change，or even if they are in a situation with abundant opportunities，they fail to achieve innovation ambidexterity mainly because of limited abilities. By clarifying the antecedents and their combined effects that affect incumbents to achieve innovation ambidexterity，this paper will provide useful reference and path guidance for undertaking corporate spin-off development.