Abstract: Against the backdrop of the accelerated global transition towards low-carbon energy, photovoltaic power generation technology, owing to its advantages such as cleanliness, environmental friendliness, and renewability, has emerged as a crucial technical pathway for optimizing the energy structure in the construction sector. Therefore, it is of great significance to conduct an in-depth analysis of the internal relationship between the selection of photovoltaic power generation systems and their cost-benefit, and to screen out the components that are best suited to project requirements and offer the optimal cost-benefit. Taking the photovoltaic project in Zhengzhou as an example, this study sorts out the interaction relationships among various factors influencing the cost-benefit, establishes a system dynamics model, and conducts a 20-year cost-benefit simulation analysis of components with different power ratings. The research shows that in photovoltaic power generation projects, the cost-benefit of 300 W, 400 W, and 500 W components all presents negative returns in the initial stage. Among them, the 400 W components achieve a break-even point in the third year, and the cumulative cost-benefit during the simulation period reaches 89070.8 yuan, which outperforms the cost-benefit performance of 300 W components (68414.8 yuan) and 500 W components (61909.8 yuan).