The feed to cracking furnace of ethylene plant is generally the mixture of gaseous raw materials and diluted steam in a certain proportion. Because the feed contains a certain proportion of steam, the measuring medium easily condenses during the actual measurement, resulting in phase instability of the measuring medium which leads to large deviations or fluctuations in flow measurement. The inaccurate measurement of cracking furnace feed flow will lead to the failure to use automatic control for the feed to cracking furnace, so that the labor intensity of process operators in monitoring DCS operation screen greatly increased, which makes it impossible for them to balance the normal control of cracking furnace, thus resulting in a short operation cycle of cracking furnace and the frequent switching of cracking furnace and then affecting the production efficiency of enterprises. By optimizing and improving the installation mode for feed flow meter of cracking furnace, the stability and accuracy of measuring instrument can be effectively guaranteed, the problem of measurement distortion can be solved, and the monitoring and maintenance intensity of measuring instrument personnel and technical personnel can be reduced, so as to achieve the long period operation of cracking furnace.