The invention relates to a method and device for recycling and refining acetonitrile in ceftriaxone sodium synthesis. The method includes the following steps: acetonitrile waste liquid in ceftriaxone sodium synthesis is fed into a first rectifying tower, and parts of water and heavy components are removed in a rectifying mode; rectified acetonitrile liquid is obtained after concentrating is carried out and fed into a neutralization tank for pH value adjustment; the neutralized rectified acetonitrile liquid is fed into a second rectifying tower for further impurity removing, the rectified acetonitrile liquid enters a pervaporation membrane separation unit after impurities are removed in the second rectifying tower, residual liquid in a kettle is returned to the first rectifying tower, and the acetonitrile in the residual liquid is recycled; the crude acetonitrile is obtained after the liquid is separated through the pervaporation membrane separation unit, water and a small amount of acetonitrile in a solution on the feed liquid side permeate a pervaporation membrane in a steam mode to obtain permeating liquid, the permeating liquid is condensed to be returned to the neutralization tank, and the acetonitrile in the permeating liquid is recycled; the crude acetonitrile obtained through the pervaporation membrane separation unit is fed into a third rectifying tower to be refined, the finished acetonitrile is obtained, acetonitrile-water azeotrope obtained after rectifying of the third rectifying tower is returned to the second rectifying tower, and the acetonitrile in the acetonitrile-water azeotrope is recycled.