Yellow phosphorus tail gas is an important source of CO for C1 chemistry if an efficient separation/purification technology is available. Presented is a four-bed pressure swing adsorption for separation and purification of yellow phosphorus tail gas. CO recovering pilot plant experiments were carried out with real yellow phosphorus tail gas in an yellow phosphorus plant with a feed flow rate of 40m(3)/h. Operating conditions for the process were optimized, the operation stability and high productivity of the process were experimentally demonstrated. CO with a purity of 99% could be produced with a recovery of 95% at a pressure lower than 0.3 MPa.