Open channel flow measuring device

The invention provides an open channel flow measuring device which comprises a bottom plate, a main supporting assembly is rotationally installed at the top of the bottom plate, and an overturning driving assembly for driving the main supporting assembly to rotate is installed on the side portion of the surface of the bottom plate; the main supporting assembly comprises a main supporting plate, a main supporting rod and a roller; side base bodies are symmetrically arranged on the two sides of the surface of the bottom plate. The inner end of the main supporting plate is rotationally installed between the two side base bodies, and the rotating connecting position is connected with the driving assembly. The outer side of the surface of the main supporting plate is vertically provided with an outward-extending driving assembly, the outer end of each group of main supporting rods is slidably sleeved with an outward-extending assembly, an ultrasonic detection case is fixedly arranged between the two outward-extend