One of the efforts to control the corrosion rate used is to add inhibitors. Corrosion is a a decrease in the quality of a material (metal) caused by a chemical reaction between the metal and its environment. The purpose of this study is to analyze the effect of temperature on the corrosive medium in the presence of plant, Myrmecodia Pendans extracts as an organic inhibitor. This study used a type of carbon steel APT 5L Grade B with temperature 30°C, 40°C, 50°C. Corrosive medium used was 1M HCl with varying concentrations of plant extracts Myrmecodia Pendans 100 to 500 mg I L. Maceration method is a method used for extracting plants, Myrmecodia Pendans. The effectiveness of the use of organic inhibitors Myrmecodia Pendans in acid known by some measurements. There are ETS and FTTR. From the results of of measurements carried out, the Myrmecodia Pendans extract able to reduce corrosion rate. The resulting best inhibition efficiency of 82,88% at 30°C temperature conditions and extract the addition of 500 mg I L. Protection system that occurs is an Myrmecodia Pendans extract form a passive film on the surface of the material so as to reduce the corrosive attack.