In previous studies, mango peel skin can be used as raw material as an organic corrosion inhibitor. This research is a continuation of previous research. The raw materials used by mango skin peel with mango leather extract concentration are improved so that the optimized efficiency is more optimal. The tests that have been done in this research are polarization test, electrochemical test, and SEM. The extract concentration used was 2-6 ml, while the corrosion solution used was HCl 1 M. From the measurement results, it was found that the corrosion rate decreased to 1.774 mm/year. The highest efficiency inhibitory result is 81.77%. Electrochemical test results are not as good as polarization test results. This can happen because it has not reached the optimum concentration. From the polarization test indicates that the mechanism that occurs is anodic inhibiting mechanism. This is supported by the results of SEM testing performed. The SEM test results illustrate the presence of a thin layer formed on the surface of the material.