The invention discloses a model test device for simulating pre-cooling freezing method construction under the flowing effect of underground water. The model test device comprises a model box, a waterflow control system, a low-temperature refrigerating fluid circulating system, a high-temperature unfreezing fluid circulating system and a measurement system. The waterflow control system makes underground water flow through the difference of water levels in water tanks on two sides of the model box. A freezing pipe simulation tunnel is excavated to form a freezing zone, underground water cooling is achieved through a pre-cooling pipe and an external high-temperature refrigerating fluid circulating pump buried at the upstream of the freezing zone, and underground water heating is achieved through an unfreezing pipe and an external high-temperature unfreezing fluid circulating pump buried at the downstream of the freezing zone. The measurement system comprises a temperature measurement system and a surface displacement measurement system. The model test device is suitable for the technical field of underground projects, can effectively research a freezing zone range and surface deformation rules under various conditions and can be widely applied to sandy soil pre-cooling freezing method research under the flowing effects of various types of underground water.