Abstract: As China’s energy industry actively implements its “Going Global” strategy, systematically evaluating and optimizing the Overseas Foreign Direct Investment (OFDI) strategies under the Belt and Road initiative is increasingly crucial. Given the complexity of the OFDI environment, this paper conducts an in-depth analysis of OFDI projects by grid enterprises. It builds a risk evaluation system from the perspective of risk management and utilizes Interpretative Structural Model (ISM) to identify and organize key risks. A multi-stage portfolio optimization model is developed to minimize risks and maximize returns. This model employs dynamic programming to solve the optimal investment portfolio under conditions of risk uncertainty. Case studies validate the effectiveness of the model and establish the optimal investment strategy. This research constructs an optimal investment strategy for grid enterprises’ international ventures, extends the theoretical study of corporate OFDI, and provides both theoretical and practical guidance for the internationalization strategies of domestic energy companies. This contributes to promoting a new dual circulation development pattern both domestically and internationally.