Fattypolyamide was prepared by reaction of (1,5-Diamino pentane) with dimeric fatty acid C36 in molten state. The reaction was performed at 110 C˚ without catalyst, then with (Phosphoric acid, Sulphoric acid and Manganese dioxides). The Kinetic study was carried out on the reaction and followed by determining the acid value of the product. The polyamidation reaction was found to be on the overall a second order up to 59% conversion. Then the reaction order changes. We found that the Catalyst increases the velocity of the reaction with manganese dioxides the best Catalyst. The Degree of Polymerization, Number Average Molecular Weight and Weight Average Molecular Weight have been calculated during different times. The relationships between Degree of Polymerization and Number Average Molecular Weight, Weight Average Molecular Weight with times are linear until 59%conversion at 110˚C with used catalysts. The highest (N.A.M.W) and (W.A.M.W) was accomplished with the Catalyst MnO2.