Abstract: The mist process of inhibitor in pipeline, the mist concentration distribution and the mechanism of protecting pipeline have been researched by means of using the mist theory of liquid in the paper. The researchers found out that the inhibitor's mist was the most sufficient in the spraying condition, which could form a homogeneous film; while the quality evaluation indices on mist angle, mist fineness, mist homogeneity and concentration distribution could also prove whether the pipeline was effectively protected or not. The above parameters related to the average grain size of misted inhibitor, particle size distribution and inhibitor concentration distributed within pipe have been calculated. Because the common gas pipeline has large diameter, and the gas generally flows in turbulent flow, the paper puts forward the equations to deal with the jetting volume of inhibitor and the minimum jetting volume which protects pipeline based on the e-conomical principle. The field measured results show that the calculated jetting volume of inhibitor is quite closed to the actual jetting volume, which proves the equations given in the paper to be reasonable and use- ful.