Abstract:  Monobore well drilling and completion technology is important for both marginal oil and gas fields and small offshore oil and gas fields. Cementing is one of the key procedures. For the difference between Monobore well cementing and traditional well cementing, this paper focus on small-size tubing. (liner) cementing technology ，to solve the problem that the 88.9mm oil tube centering problem，poor replacement efficiency, the difficulty of scraping for small-sized tube, and tube cleaning problem. The technology has been successfully applied on an oil and gas field in the East China Sea and achieved good results.