Sir if i say that the molecules have to cross an energy barrier for the reaction to proceed in kinetics and for this they need activation energy.We know that catalyst can lower the energy barrier, then can a catalyst can make a non spontaneous reaction to occur by lowering the energy?.IF I AM WRONG THEN WHAT IS THE PROBLEM IN MY STATEMENT?

No, a catalyst cannot alter the equilibrium position (or constant) one bit, as it does not change the initial and final states (and thus the thermodynamic properties of them). It only creates a different pathway, with a much faster slow step (usually because the new slow step has a much lower activation energy barrier). This increases both the forward and reverse reaction rates by the same factor such that a system at equilibrium will not “shift” in either direction if a catalyst is added. So since the addition of a catalyst cannot change the thermodynamic tendency for a reaction to occur (net) at all, it certainly cannot make a reaction that is nonspontaneous (i.e., has a tendency to occur in the reverse direction at certain conditions) become spontaneous (i.e., has a tendency to occur in the forward direction at those same conditions). Addition of a catalyst will merely increase the rate at which a system reaches equilibrium—it will not alter the composition of the system once it gets to equilibrium.