Upper bound on the supersymmetry breaking scale in supersymmetric SU(5) model.

The status of coupling constant unification in standard supersymmetric SU(5) model and its extensions is discussed. Taking into account uncertainties related with the initial coupling constants and threshold corrections at low and high scales we find that in supersymmetric SU(5) model the scale of supersymmetry breaking could be up to $10^8$ Gev. In the extensions of standard SU(5) model it is possible to increase the supersymmetry breaking scale up to $10^{11}$ Gev.