This paper deals with electrical characteristic of Single-Electron Transistor (SET). The Current- voltage (I-V) characteristic of the SET is predicted according to various capacitance parameters. The Process of simulation is based on analytical transistor model. The effect of tunnelling capacitance on the I-V characteristics of SET are systematically computed assuming source and drain are connected by quantum dot. The Steady state equation is solved by considering the tunnelling mechanism. We calculated free energy changes as a function of equivalent circuit parameters and background charge. Tunnelling probabilities on drain and source terminals are determined using Fermi’s Golden Rule. The SET is the simplest device wherein coulomb blockade effect can be observed.