Abstract: The simulation of ethylene plant needs accurate data of cracking furnace feedstock which is difficult to get. The simulation of feed system makes it possible to get the cracking furnace feedstock data base on the feedstock data of plant which is easy to get. This paper simulated a feed system of a petrochemical ethylene plant and reconciled the redundant flowrate measurement with the data rectification technique. The data rectification technique solved the problem of data disequilibrium and data missing. We also proposed a method of dealing with negative data appeared in data rectification. Finally, we got accurate and reliable cracking furnace feedstock data.