A measuring device includes a furnace, a draining vessel, a loader and a computing system for physical properties. The draining vessel with molten metal fluid is in the furnace. The loader accumulates the molten metal fluid from the draining vessel. The computing system includes a recording unit, transform unit, computing unit and processor. The recording unit records the vessel information. By the assumed physical parameters and the vessel information, the transform unit transforms a weight of the molten metal fluid in the loader into a first length criterion, and the computing unit simulates the flowing of the molten metal fluid to have a second length criterion. The processor minimizes the difference of the first and the second length criterion by changing the assumed physical parameters. The physical properties of the molten metal fluid are determined when the difference is minimized.