  The recently discovered burst of gravitational waves GW150914 provides a good
new chance to verify the current view on the evolution of close binary stars.
Modern population synthesis codes help to study this evolution from two main
sequence stars up to the formation of two final remnant degenerate dwarfs,
neutron stars or black holes [Massevich 1988]. To study the evolution of the
GW150914 predecessor we use the "Scenario Machine" code presented by [Lipunov
1996]. The scenario modelling conducted in this study allowed to describe the
evolution of systems for which the final stage is a massive BH+BH merger. We
find that the initial mass of the primary component can be $100\div 140
M_{\odot}$ and the initial separation of the components can be $50\div 350
R_{\odot}$. Our calculations show the plausibility of modern evolutionary
scenarios for binary stars and the population synthesis modelling based on it.
