Gamma ray bursts are energetic and most luminous objects in the universe. They emitrnthe most energetic form of electromagnetic radiation with extremely short wavelength andrnhigh frequencies. The gamma ray burst which is detected by swift Burst Alert Telescopern(BAT) with giant and bright rnare is GRB 050502B with the energy band (0.3 - 10.0 keV).rnIn this thesis we have tried to theoretically reconstruct the X-ray after-glow from GRBrn050502B as observed by NASA`s Swift satellite based on current GRB model