Existing research on risk sharing management often ignores the adverse consequences of secondary risks. This study addresses secondary risks that emerge from the implementation of specific risk mitigation measures. Addressing the limitations of existing research that overlooks secondary risks and exploring the impact of secondary risks on the outcome of risk sharing, this paper integrates secondary risks into a game model that examines risk sharing between the public and private sectors in EPC+PPP projects. Utilizing a risk-control benefit model, an evolutionary game model is established to determine the evolutionary stability strategy under various conditions. This encompasses factors such as project income distribution, risk control capability, imbalanced status, and risk compensation. The findings indicate that secondary risks impact the risk-sharing strategies of both parties. Furthermore, a stronger risk-control ability correlates with a greater inclination toward risk-taking. The public sector can motivate risk sharing for the private sector through risk compensation, with a discernible lower limit. Ultimately, risk sharing becomes an active choice for both public and private entities when the risk cost is below the difference in returns between risks.