The question of the state of the Russian army in 1917 is considered. The complex and contradictory situation on the front line of the theatre of military operations in the conditions of preparation and carrying out offensive operation in the summer of 1917 is described. The presented range of sources illustrates insufficiently studied pages of the history of the Great war. The analysis of the sources allows to understand how the transformation of the consciousness of the soldier’s mass and revolutionary moods in the army took place. The process of evolution of views on the war, expressed in letters from the front to the rear, as well as in the materials of the Bolshevik newspaper “Okopnaya pravda” is shown. Based on the analysis of archival documents of the 6th Finnish infantry division, which for the first time became the object of research, an objective picture of military everyday life on one of the important front sections on the eve of the final events of the First World War and the Great Russian revolution of 1917 is presented. The author draws attention to the personal relations between the command staff and the lower ranks in 1917. It is shown that in the conditions of the Great Russian revolution the consciousness of not only soldiers, but also the officer corps, revolutionizing under the influence of real events, as well as the propaganda work of radical parties, is transformed.