The invention discloses a trimethylamine tail gas recovery system and method, and belongs to the technical field of chemical engineering and waste gas treatment. Trimethylamine tail gas generated by areaction kettle enters from the top of an absorber through a gas pipe; an absorbent in a circulating tank is pumped into the upper part of an absorber through a pump to form a liquid film; absorptionliquid after reaction is discharged into the circulating tank from the lower part of the absorber; and tail gas is discharged into a vacuum unit from the bottom of the absorber; the tail gas is pumped to an exhaust funnel through a vacuum unit, and is discharged at high altitude after being detected to reach the standard by an on-line monitor; when the discharge rate of trimethylamine in the online monitor is greater than 80% of the discharge standard, the absorption liquid in the circulating tank is pumped into the reaction kettle to realize recovery of trimethylamine in the tail gas, and finally p-methylbenzyl chloride in a metering tank is pumped into the circulating tank. According to the system and the method, the recovery of trimethylamine in the tail gas is realized, the tail gas emission can reach the standard, and gas-liquid parallel flow is controlled; the method can be carried out at room temperature without heating, so that the energy consumption is reduced, and the comprehensive economic benefit is improved.