The paper is focused on the study of the dynamic surface properties of mixed monolayers of porphyrin and arachidic acid with various mole fractions at the air–water interface. The choice of porphyrin solid thin film as an object of study is explained by its high potential application in the area of photovoltaics and medicine. The Langmuir monolayers of porphyrin and arachidic acid were formed under different conditions using the Langmuir-Blodgett technique. The increase of subphase temperature led to a decrease in the rigidity of the porphyrin monolayer and leads to accelerating the relaxation process of the monolayer. The chosen surface pressure (4, 5, 15 and 35 mN/m) affected the stability of the floating monolayer. The higher miscibility of the monolayers was obtained at the mole fraction of porphyrin = 0.333. The change in the phase of monolayers surface was reported on the basis of surface potential data. The morphology properties of the mixed systems transferred on silicon substrates by Schaeffer method are studied.