The invention provides a production method for an automobile exterior board. According to the production method, extremely low surface waviness W(CA) can be obtained by controlling the surface roughness of a chilled hard steel plate before annealing and performing two flatness treatment after annealing under the condition of ensuring that the average surface roughness Ra of the steel plate meets the stamping requirement. The average surface roughness Ra of the steel plate can be controlled between 0.8 to 1.6 microns, the waviness W(CA) of a filter center line can be controlled between 0.6 to 0.3 microns, so that the coating quality of the automobile exterior board can be favorably improved, the stamping performance can be enhanced, the reject ratio of products can be reduced, and the production method can meet the usage requirement of an automobile factory.