To inquire aims of diversification as the most important Russian enterprises resultatives increase mechanism, the article considers scheme of enterprise functioning in diversification motives and aims interconnection and executes analyzing firm activity character change with its diversification and character of financial impact on its diversification. Analyzing particular diversification aims has allowed considering threats and negative factors, obligate to taking into account in forming enterprise activity diversification strategy to taking into account its specialties. Forming enterprise activity and financial sustainability basic assessing figures ordered graph and considering their calculation formulas has allowed modeling this graph. Practical realizing modeling enterprise activity diversification and financial sustainability basic figures ordered for a research object – St-Petersburg oil-gas machine-making enterprise taking into account presented graphic interpretation of its financial condition shows this research practical sustainability and opportunity to spread into other industries. The elaborated graph is the basis to form economically-mathematical models and algorithms of defining several kinds of enterprise’s credits. Besides that, it is one of effective instruments of complex economic analysis, which is the base of backgrounding potential enterprise development destinations with statistic modeling enterprise production process parameters. Therefore, elaborated graph practical realization helps to sufficient increasing effectiveness of managing enterprise.