An intelligent control method for the pyrolysis furnace in ethylene plant features that the model to measure heat value of fuel gas, which is developed by fuzzy nerve network, the real-time feedforward deduction control based on said model, the expert system for heat distribution of the side wall and bottom of said furnace, the outlet temp control system for furnace tubes, equivalent and total throughput control system for outlet temp of furnace tubes, and on-line self-correcting control system of the mass flow ratio of input gas/hydrocarbon are used.