The invention provides a full-scale model test platform for sand filling of a foundation of an immersed tube tunnel. The full-scale model test platform for sand filling of the foundation of the immersed tube tunnel comprises an experimental tank, wherein the experimental tank is divided into a sand filling test region (12) and a model manufacturing region (15) through a partition (14); and side slopes (11) are arranged on the periphery of the experimental tank, namely, the area of an opening of the experimental tank is greater than that of the bottom surface of the experimental tank, and a plain concrete cushion layer is further paved on the bottom surface of the experimental tank. By the full-scale model test platform for sand filling of the foundation of the immersed tube tunnel, influence of single-hole sand filling, sand filling construction sequence and relevance thereof to the sand filling effect can be researched, and furthermore, influence of the position of a sand filling hole to the sand filling effect can be researched. The full-scale model test platform for sand filling of the foundation of the immersed tube tunnel has the advantages of various test working conditions, visual and effective sand filling monitoring effect, and model reusability. The full-scale model test platform for sand filling of the foundation of the immersed tube tunnel is an important tool for checking a construction process for sand filling of the foundation of the immersed tube tunnel, determining a monitoring method in a sand filling construction process and formulating a sand filling effect evaluation standard.