The present invention discloses an optimization method for adjusting a production load of an ethylene cracking furnace. The method comprises the following steps: step 1: establishing a geometric model of a radiant coil of a cracking furnace to calculate an operating parameter inside the radiant coil of the cracking furnace; step 2: establishing a geometric model of the cracking furnace to acquire an operating parameter outside the radiant coil of the ethylene cracking furnace; step 3: with reference to a calculation result of step 1, iterating a calculation result of step 2, and performing coupling and recalculating; and step 4: when the feeding amount of the cracking furnace ranges from 70% to 120% of a load, adjusting a fuel flow rate to 0.6Q-1.2Q until the calculated operating parameters of the cracking furnace are superior to the operating parameters of the cracking furnace before the load changes. According to the optimization method for adjusting the production load of the ethylene cracking furnace disclosed by the present invention, the production load of the ethylene cracking furnace is adjusted; the optimum heat distribution is provided for the radiant coil of the ethylene cracking furnace, so as to reduce energy consumption of the ethylene cracking furnace; and the optimization method for adjusting the production load of the ethylene cracking furnace is provided according to types and features of materials.