Objective To investigate the inhibition performances of three amines including octadecylamine, unsaturated octade-cylamine and N-octadecyl trimethylene diamine in the 1 mol/ L HCl solution and further explore the film-forming property and inhibition mechanism of the three organic amines. Methods Static weight-loss method, potentiodynamic polarization, contact angle and AFM force curve measurement were used to investigate the film-forming ability and the film uniformity of these three organic amines on the metal surface. Results The inhibition efficiency of unsaturated octadecylamine, belonging to the cathode type inhibitor, was significantly higher than the other two organic amines. The contact angle measurement showed that the hydrophobicity of the unsaturated octadecylamine film reached the excellent grade, higher than the other two organic amines. Its inhibition mechanism was to form a dense and hydrophobic film on the metal surface so as to prevent the metal from contacting with the corrosive medium. In the adhesion strength test, the measured data distribution of the unsaturated octadecylamine on the metal surface was more uniform, and its standard deviation was the smallest, indicating that its film homogeneity was the best. Additionally, the mean adhesion force of the unsaturated octadecylamine on the metal surface was the highest. Conclusion The unsaturated octadecylamine has the best corrosion performance among the three amines.