  We study and solved Schwinger-Dayson equation for massive quarks in the quark
model. Interaction potential is choose as sum oscillator and Coulomb terms. The
calculation show us that negative energy of quark exist under $m_{o} \ll \Vo$
i.e. when mass quark is less that parameters of scale. Us are offered to use
asymptotical behaviour at the solutions Schwinger-Dayson equation selection
physical and non-physical conditions. The quark condensate under different
values mass quarks are calculated. The scale parameters $\Vo$= 520 MeV.
