The classical power generation expansion planning (PGEP) that takes environment as an exogenous variable is mainly used to optimize the specific expansion scheme for power companies. It is not suitable for the national energy strategy which is closely related to macro-economy growth and environmental protection. To address this complex problem, a novel multi-disciplinary framework for power generation mix planning is proposed from the perspective of economic growth. In this model, an endogenous economic growth model is introduced to describe the equilibrium relationships of various sectors in macro-economic, thus making economy and environment the endogenous variables. By establishing a new soft-linking between these two models, it permits policymakers to evaluate the alternatives and trade-offs between economic growth and environmental protection within long-term planning horizon while guaranteeing the feasibility of planning scheme. To demonstrate the effectiveness of the proposed methodology, a case study of China from 1990 to 2040 is implemented.