The problem of investigating the impact of taxation on the behavior of economic agents remains relevant within a long period of time. This is due, on the one hand, to the multiplicity of channels of this influence, which cover different aspects of people's activity (consumption, investment, employment etc.), and on the other – due to the importance of this issue for the economic government policy. One of the powerful channels of the influence of taxation on the economic agents’ activity of is opportunism as a behavioral property. The effect of this channel is tax evasion – one of the most pressing issues within this range of problems. The article proposes a system-dynamic model that takes into account traditional factors that influence tax evasion (tax control parameters), as well as the assumption that people's tax behavior can be determined by their financial status. The model allows to adjust the parameters of taxation and tax control, as well as the elasticity of reaction of economic agents as for tax evasion, depending on their level of income. Three groups of agents by income criterion are considered, the transitions between groups is modeled as a non-stationary Markov random process with the calculation of conditional transition probabilities at each time step, depending on the indicators of tax control effectiveness. Further directions of the study foresee detailed substantiation of the parameters of the model operators on the basis of the research of real regularities, that determine the intergroup dynamics and mechanisms of evasion, characteristic for different income groups. The model can be used as a virtual training ground, providing extensive experimentation options to test various theoretical assumptions and to study the influence of exogenous factors on the dynamics of endogenous variables, as well as building regression meta-models that will reflect the dependence of the selected response functions of the a number of exogenous factors, taking into account their combined effect.