Metastable steels, in particular, with the TRIP effect, have advantages over other steels due to the combination of strength and plasticity because of the peculiarities of their microstructure. The article presents the results of a study of the mechanical properties of aluminum-modified TRIP steel. Samples were obtained in the laboratory by traditional method of metallurgical manufacturing. The mechanical properties were investigated by tensile, compression testing methods, as well as by instrumental indentation (Berkovich method). During the tensile tests, the tensile curves of samples with different deformation rates and the values of the proof yield strength under compression were obtained, an experimental hardening curve of TRIP steel modified with aluminum was constructed. The Berkovich method obtained an array of data "load — depth of indentation", which is used to determine the hardness on the Martens scale, indentation hardness, modulus of elasticity, creep during the indentation, as well as the proportion of elastic component work during the instrumental indentation. The results obtained are of great practical importance in the development of technologies for the production of structural products from TRIP steel modified with aluminum.