The invention relates to a measuring system for measuring the height and diameter of moving workpiece, which consists of a uniform speed moving device, a height measuring mechanism, a diameter measuring mechanism and a minisize programmable logic controller (PLC) disposed on a aluminium section bar support; the uniform speed moving device, the height measuring mechanism and the diameter measuringmechanism are all connected with the minisize programmable logic controller (PLC) through the buses in site; and the programmable logic controller (PLC) is connected with the interface of the upper layer control system WinCC. The invention provides to a measuring system for measuring the height and diameter of workpiece on line, especially the mechanical structure of the system and control systemscheme; and the measuring system achieves the advantages of simple manufacturing technology, low manufacturing cost, accurate measuring, high automation degree, easy adjusting, small volume, and convenient transporting and carrying.