Based on the data of foreign direct investment (FDI) and carbon emissions (CE) data in Zhejiang Province from 1995 to 2021, this article utilizes nonlinear dynamic methods to construct a nonlinear dynamic system model (FDI-CENLDS) to empirically examine the relationship between FDI and CE. The results show that: (1) A nonlinear interaction exists between FDI and CE. When carbon emissions exceed 479.41 million tons, the growth of FDI begins to inhibit the growth of carbon emissions. Carbon emissions also indirectly affect the growth of FDI. The FDI growth rate is suppressed when carbon emissions exceed 126.11 million tons. (2) The FDI-CENLDS system exhibits stable attractors. The optimal scale of FDI is 32.98228 billion USD and the optimal scale of carbon emissions is 493 million tons. There is still significant room for FDI development in Zhejiang Province compared to the optimal scale. Meanwhile, carbon emissions are slightly below the optimal scale. Therefore, it is recommended to further enhance the promotion of FDI and encourage FDI in green industries. These suggestions will enable Zhejiang Province to reduce the growth of carbon emissions, while simultaneously promoting economic development and achieving a balance between economic growth and the ecological environment.