Disclosed is a propulsion system and a rocket having the same. The propulsion system includes: a combustion tube having a propellant therein; a nozzle installed at a rear end of the combustion tube, and configured to discharge combustion gas generated when the propellant is ignited; and a nozzle separation unit coupled to the combustion tube and the nozzle, respectively, and configured to mount the nozzle to the combustion tube, and configured to separate the nozzle from the combustion tube as at least part thereof melts when reaching a preset temperature.