In this work, the possibilities of the Korelia program for analysis of dynamic processes by the phase plane method are explored. The dynamics model is described using a specialized programming language. An algorithm for constructing nullclines of the process and for calculating equilibrium points is presented. The type of points is determined by the state matrix eigenvalues. All derived dependencies and parameters are displayed in graphical form. The approach is illustrated by a model of plasma renin activity after treatment of experimental animals with nicardipine. The special point is initial condition and it is of the stable focus type.