The article provides system analysis of small business. The paper presents quantitative indicators of the development of the subjects of Russian small business contained in various statistical databases (Rosstat, Federal Tax Service), reveals the incompatibility of the data, which complicates the analysis of the considered sector of the national economy. It is concluded that the scale of development of small business is insufficient, which does not allow for the full implementation of its inherent functions. The necessity of supplementing the quantitative approach with a qualitative analysis of small business as a mesoscale system has been substantiated. The concept of heterogeneity of its structure is introduced, characterized by the presence of a triad of categories (“kids”, “genetic dwarfs”, “transformers”) and a triad of subcategories (“travelers”, “reorganizers”, “imago”) that determine the composition of “transformers”. Their system functions have been studied and it was concluded that the relationship between them, on one hand, determines the systemic stability of small business, and on the other hand, creates a “portrait” of small business in a particular state. Based on the proposed methodological principles, the specificity of the Russian small business model has been formulated, namely that the SME sector is currently not able to be the basis of a market economy, and the model itself is structurally unbalanced. Its distinguishing features include a low share of innovative oriented enterprises comprising “kids” and “dwarfs”, a significant number of small firms working in economic symbiosis with large enterprises, a relatively short life cycle of all categories of small businesses, a high share of imago and retiring due to the loss-making of small enterprises etc. The specifics of the implementation of micro-level development strategies of various categories of small enterprises is the use of credit resources of banks, increasing the stability of their functioning (including increasing their life cycle) have been considered. The necessity of a differentiated approach to the implementation of the mesoscale strategy of state support of small businesses has been substantiated. The conclusion has drawn on the importance of transforming the existing infrastructure to support Russian small business, and in particular – the importance of the role of state aid in times of crisis. Supporting measures for small enterprises in the context of the corona-virus pandemic in Russia and in foreign countries have been considered.