The invention provides a durable antibacterial antistatic woolen sweater finishing agent. The finishing agent is prepared by compounding the following raw materials: ester-based quaternary ammonium salt, copper omadine, N-alkyl betaine, polyvinyl alcohol, alkyl polyglycoside, citric acid, isothiazolinone, white carbon black, ADK ABDO-200, bentonite, hydroxypropyl methylcellulose, sodium polyacrylate and deionized water. Woolen sweater fabric treated by the finishing agent has excellent durable antibacterial antistatic properties, and a finished woolen sweater is soft and comfortable. The woolen sweater further has an anti-yellowing property, the formula of the finishing agent is optimized, the raw material amount is less, and the cost is low.