The invention discloses a method and a device for continuously producing dyes. The method comprises the following steps: adding diazotization reaction raw materials into an ingredient kettle, controlling temperature in the kettle, allowing the materials to flow in a tubular reactor through an overflow orifice, detecting the reaction state through an online detection device, continuously discharging the diazotization compound solution obtained through the reaction, continuously feeding the diazotization compound solution and a coupling component solution according to a specified ratio, allowing the materials to flow into the tubular reactor through the overflow orifice, detecting the reaction state through the online detection device, transferring the coupling reaction materials into a crystal transformation kettle, performing crystal transformation, and performing filter pressing to obtain a dye filter cake, wherein the filter cake mother solution and the wash water are circulated for preparing the coupling component solution. The reaction temperature, material flow and reaction state detection device are automatically subjected to interconnected control. According to the method, automatic and continuous dye production is realized, the production capacity, the product quality and yield are improved, the labor intensity and working conditions of workers are improved, the waste water, water gas and waste residue amounts in the dye production process are greatly reduced, and circular economy and cleaner production process are realized.