A supersymmetric model with gauge symmetry G 1 xG 2 , where G i =SU(3) i xSU(2) i xU(1) i , is constructed within the framework of gauge mediated supersymmetry breaking. At the energy scale ~(10-100) TeV where the gauge symmetry breaks down to the Standard Model (SM), G 1 is strong and G 2 is weak. The observed gauge coupling constant unification of the SM is attributed to that of G 2 . The messenger fields and Higgs fields just satisfy the condition that makes G 2 a realization of strong unification. The SM gauginos are predicted to be generally heavier than the sleptons and squarks.