Abstract: Mcrocomputer and an intelligent software embodied are used, so as to simulate expert's design ideas to minimize the hardware construction in related instrument and to improve its function, intelligent compensation accuracy of the reference junction of thermocouple can be better than 0.02℃, whereas the compensable temperature range of the circumstance is-200-650℃; the on-line design accuracyof flow measurement system with a variable pressure-drop type throtlling element is better than 0.2%.