In order to improve the efficiency of pipeline transportation, it is necessary to study the methods to reduce the resistance of pipeline transportation. When the natural gas is transported in the pipeline, most of it is in the square resistance area, and the friction coefficient of the pipeline is only related to the roughness of the pipe wall. In natural gas pipeline, the V-shaped riblets can reach the effect of drag reduction. The V-shaped riblets on two different dimensions of small diameter pipeline were simulated by FLUENT and compared with the large diameter pipeline. In general, under different flow rate, the output of the h=s=0.51mm V-shaped riblets are the drag reduction effect of gas pipeline, while the h=s=0.90mm V-shaped riblets pipeline is increasing resistance in velocity higher than 7.5m/s; the large diameter pipeline has better drag reduction in symmetrical V shaped riblets when h=s=0.9mm, and the small diameter pipeline with better drag reduction in symmetrical V shaped riblets when h=s=0.51.