Abstract: Inhibitor pre-film of gas pipeline is advantageous economically and technically, but there is less studies on its basic theory and application. Under this background, the inhibitor pre-film technology is discussed in this paper. Considering the basic technical principle of inhibitor pre-film technology, its mechanism is analyzed. The advantages and disadvantages of various inhibitor pre-film devices are explored, and specific recommendations are proposed for improving the devices. Moreover, several common quality evaluation methods for inhibitor pre-film are presented. The results show that the film forming by adsorption is the chief mechanism of inhibitor pre-film; exiting inhibitor pre-film devices are mainly unfavorable for incomplete pipeline pre-film or inhibitor filling quantity limited by the pig size, so dual-pig full circumferential jet pre-film technology is recommended to improve such devices; the inhibitor pre-film quality shall be evaluated combining with inhibitor film thickness measurement and pipeline corrosion rate monitoring results.