Unsteady cooling problem with conduction and radiation is examined here for a finite cylindrical medium that is exposed to the rarefied cold environment. To solve the energy conservation equation and radiative transfer equation, the finite difference technique with the Crank-Nicolson scheme and the discrete ordinates method were chosen respectively. A parametric study was performed to find the effects of optical diameter, conduction-to-radiation parameter and scattering albedo. Cooling characteristics were discussed through the mean temperature and emittance of the medium. It has been greatly affected by those parameters.