The invention relates to a continuous production method of a multi-kettle serial triazine herbicide. A metered cyanuric chloride solution is pre-cooled and mixed with alkylamine R1 in a mixer to entera first-stage reaction kettle, continuous discharging is conducted, after a heat exchanger is passed, the cyanuric chloride solution is neutralized with alkali in the mixer and enters a first-stage neutralization kettle, after a reaction is completed, the cyanuric chloride solution passes through a continuous water separator and the heat exchanger and is mixed with alkylamine R2 in the mixer to enter a second-stage reaction kettle, the continuous discharging is conducted, after the cyanuric chloride solution passes through the heat exchanger, the cyanuric chloride solution is mixed with the alkali in the mixer to enter a second-stage neutralization kettle, after the neutralization, a aqueous phase is separated by a continuous layerer, a solvent is removed, and drying is conducted to obtain a triazine product. The production method has the advantages of high productivity, good production stability, high efficiency, high product quality and the like, is particularly suitable for technical transformation of existing production enterprises, has a low transformation cost, basically does not add novel reaction equipment, and is easily mastered by existing enterprises.