This article suggests an approach to evolutionary modelling of the financial sustainability for the elements of a meso-economic systems. The evolution of said elements is connected with transition from the unstable state of the system to the more effective and stable state. Possible evolutionary trajectories of the system are shown to depend on internal parameters. The evolutionary approach to modelling the elements of meso-economic systems allowed to examine the financial sustainability of such systems as one of the states of their evolutionary development and to show the necessity of transition from the unstable state of the system into a new stable state. In order to assess the state of the enterprise in the examined period and to define its trajectories in the future, calculations with real data were performed. These calculations allowed to estimate the possibility of elements of the meso-economic systems making a transition from the stable state into the state of instability, to construct the evolutionary trajectories of the existing enterprise as an element of the meso-economic system depending on the values of internal parameters with the help of evolutionary modelling. In particular, it was deduced through sustainability analysis using the evolutionary approach that the enterprise developed a stable state trajectory in the examined period; analysis showed, that such state of the enterprise entails limitation for further development, and there are several possible types of trajectory of development for an enterprise: saddle, center, steady knot, stable focus, unstable knot, unstable focus; the unstable state gives an opportunity to the enterprise pass into a new stable state more or less efficiently through the bifurcation point; the areas for different types of evolution were shown and the coefficient values at which the enterprise is capable of passing not only through the stable into the unstable state but also from one area to another were calculated.