Pension schemes are one of the most important and essential tools for ensuring and securing a minimum for old age people’ s standard of living. Hence, governments design and provide pension schemes. However, many challenges are faced by pension funds around the world. The most common type of pension schemes are Defined Benefit (DB). These type of pension schemes are running a significant deficit. Hence, experts attempt to reform the pension systems. Hybrid private pension plans are one of the most appropriate alternatives. Because of their unique characteristics, such as good governance, competitiveness and risk-based supervision, these types of plans are more efficient. Consequently, in this research we study the financial feasibility on the implementation of these plans. We investigate the financial feasibility using Fuzzy Cognitive Mapping (FCM) in order to identify factors affecting the sustainability of pension schemes. Then, We determine the effect of each factor on financial sustainability. Finally, using the methodology of system dynamics (SD), the model is simulated and tested. While twenty-year simulation results indicate unsustainability of DB plans, hybrid pension plan’ s cash flow shows an incremental trend.