van der Waals (vdW) force, a relatively weak and short-ranged fundamental physical interaction, is ubiquitous in nature. It plays a crucial role in understanding a wide range of physical processes as well as in the design of nanoscale devices. Existing theoretical descriptions are mostly based on the assumption that vdW interaction only “propagates” in the very small vacuum gap between two surfaces given its very short range, so that material polarization can be safely ignored. However, such assumption might not be entirely true for two-dimensional (2D) materials, for which the material thickness is comparable with the range of vdW force, and often vdW interaction “propagates” not only in vacuum but also through the 2D materials. In this work, we propose a theoretical approach that explicitly takes into account material polarization for the calculation of vdW force. By introducing “vdW polarization”, i.e. an effective dielectric response, and borrowing concepts from electrostatics, our theory quantifies the propagation and coupling of fluctuating electromagnetic fields in heterogeneous space where 2D material and vacuum are both present. We find that such “vdW polarization” can result in a perturbation term to both the strength and distance dependence of vdW force. Our theoretical framework provides a practical approach for describing and analyzing vdW force in complex dielectric environments, particularly in 2D heterostructures, and offers a useful theoretical basis for understanding and tuning interfacial coupling in low-dimensional material systems.