Well drilling export flow measuring device relates to flow monitoring field, especially relates to a well drilling export flow measuring device. The utility model provides a well drilling export flow measuring device, it can make outlet conduit stationary flow, full packages, and the sand removal is swiftly convenient, the early well kick lost circulation of discovery that can be accurate. Include: tube group, flowmeter and section flow box. The flowmeter sets up in well head get pulp mouth and on cutting the straight pipe between the flow box. Cutting flow box and being the open case column structure of an upper surface, a baffle sets up in the box with cabinet bottom surface with being certain angle, through two slides that are parallel to each other and box swing joint. One adjusts the pole is connected with the rotation of case mouth through a fixing device, is provided with a nut on the baffle, adjusts the screw rod and the nut and threaded connection of pole. Baffle one side, the last slurry drain that is provided with of cabinet bottom surface, be provided with into mud drainage tube on the box lateral wall of baffle opposite side. Tube group's head end links to each other with well head get pulp mouth, and tube group's end links to each other with the mud drainage tube that advances that cuts flow box.