Corrosion is a change in material properties, especially metals due to reactions with the surrounding environment. Corrosion tends to reduce the mechanical quality of the material. One way to inhibit corrosion is to add an inhibitor. Organic inhibitors are inhibitors that are considered environmentally friendly. In this study we will analyze the surface characteristics of adding papaya leaf as a barrier. The material used is API 5L Grade B steel in 1M HCl solution as a corrosive medium. The concentration of extract used to 0.5 - 2.5% of the amount of HCl solution. In this analysis, the results of polarization and FTIR test data will be used. Based on the results of tests that have been conducted, there is a decrease in the corrosion rate of API 5L Grade B steel in a 1M HCl solution when added papaya leaf extract inhibitors. In the potentiodynamic polarization test, the corrosion rate of absence inhibitors was 21.43 mm/year. While testing with the addition of the highest inhibitor 2.5% the corrosion rate fell to 0.4 mm/year with an efficiency of 97%.