According to the invention, a production mode comprises: generating a monoquaternary ammonium salt intermediate, and then generating a target biquaternary ammonium salt product, wherein the whole production process achieves continuous production of continuous feeding, continuous mixing, continuous reaction and continuous discharging mainly through a static mixer and a continuous reactor; the production method is simple and easy to operate, a variety of biquaternary ammonium salts can be synthesized, and the equipment utilization rate is greatly increased through the continuous production modeso as to shorten the production period; and the use and the recovery treatment of organic solvents are avoided in the production process, no three wastes are generated in the whole process, and the method is environmentally friendly.