The invention provides a method for improving an F-C acyl chloride reaction yield, comprising the following steps of: controlling an acyl chloride dripping speed in a feeding process by monitoring real-time production of hydrogen chloride; and/or controlling a temperature rise speed of a reaction kettle by monitoring the real-time production of the hydrogen chloride; and finally, judging whether the reaction is finished or not by monitoring the real-time production of tail gas. A reaction device comprises a material acylating agent dripping device, an acylating reaction kettle, a water cooling device and a tail gas absorbing device; the discharging end of the material dripping device is connected with the feeding end of the acylating reaction kettle; a material valve for controlling an inlet amount of a put-in material is arranged between the discharging end of the material dripping device with the feeding end of the acylating reaction kettle; a vapor valve for controlling a heating speed of the reaction kettle is further arranged on one side on the acylating reaction kettle; and the gas inlet end of the water cooling device and the gas outlet end of the acylating reaction kettle are connected through a gas discharging pipeline, and the gas outlet end of the water cooling device is connected with the inlet end of the tail gas absorbing device through the gas discharging pipeline. The device further comprises a gas monitoring device arranged on the gas discharging pipeline.