Abstract: Alkyl alcohol reacts with phosphorus pentoxide to form alkyl phosphate monoester. After a further reaction with alkylsiloxane, six-membered ring alkylsiloxane-phosphate esters compounds with alkyl-chains of 12 and 18 carbon atoms respectively are formed to be the inhibitive DRA on gas pipeline. The mechanism of drag reduction includes the reduction of pipeline surface roughness and a moving wave by elastic molecular film. Under the etching conditions of 50 ℃ and neutral solution of sodium chloride with nitrogen mass fraction of 5%, the results of static weight-loss method show that the inhibition efficiency of alkyl chain of 12 carbon atoms is 86.7% while that of alkyl chain of 18 carbon atoms is 83.9%. Loop simulative evaluation indicates that the drag reduction efficiency of alkyl-chains of 12 carbon atoms is 10.6% and that of alkyl-chains of 18 carbon atoms is 11.2%.