Abstract: In accordance with the four main influential factors of internal corrosion in natural gas pipeline including H2S, CO2, corrosion inhibitor and water, mathematical models are built up for single and dual factor variance analysis in the corresponding mathematical statistics. The effects of H2S, CO2, corrosion inhibitor and water and their combinations on internal corrosion in pipeline are determined with field data and through data analysis. Corresponding measures to improve internal corrosion prevention of natural gas pipeline are presented based on the analytical results.