River model topographic survey system

The utility model provides a topographic survey system for a river model, which comprises survey rails, a survey bridge and a survey trolley, the survey rails are arranged on two sides of a river channel of the river model at two ends of a to-be-measured cross section at equal elevation, the survey bridge clings to the to-be-measured cross section and stretches across the river channel of the river model to be arranged on the survey rails, and the survey trolley is movably arranged on the survey bridge; the measuring trolley comprises a structural firmware, measuring hardware, an advancing system and a circuit system, and the measuring hardware, the advancing system and the circuit system are mounted on the structural firmware; the measuring hardware comprises an underwater ultrasonic probe, an overwater ultrasonic probe, a laser range finder and a laser reflecting plate, and the fixing positions of the underwater ultrasonic probe and the overwater ultrasonic probe are perpendicular to the central axis of the