A review of modern frequently used methods for diagnosing the mental development of preschool children from the point of view of the content of tasks in them, reflecting the sensory-motor development of the child, is carried out. The fragmentation of the tasks used was revealed, the predominance of certain types in comparison with others, which ultimately complicates the diagnostic process, if it is necessary to obtain a complete picture of sensory-motor development in each specific case. A strategy is proposed for the selection and formation of a set of tasks in the diagnosis of sensory-motor development based on the theory of level organization of movements by N. A. Bernstein and the model of the functional structure of cognitive processes by B. M. Velichkovsky.