A method for on-line continuous recovery of excess nitric acid in nitration reaction is provided. Nitration reaction liquid and nitrogen gas are simultaneously conveyed to a mixer, mixed and transferred to a temperature-controlled corrosion-resistant column for on-line continuous evaporation, where the nitration reaction liquid enters the temperature-controlled corrosion-resistant column from a top end, and the waste gas and excess nitric acid are discharged from a top port of the temperature-controlled corrosion-resistant column, and nitric acid is recovered. The nitric acid-free liquid is discharged from a bottom end of the temperature-controlled corrosion-resistant column by a pump.