The quasi-one-dimensional vibrational-nonequilibrium nozzle flow of nitrogen gas is calculated numerically by using a time-dependent analysis. The explicit MacCormack scheme is used for the numerical solution. The vibrational-nonequilibrium effects of various flow parameters have been discussed and the important factor has been found. It is shown that for some practical nozzle conditions, the vibrational-nonequilibrium effects have significant influence on the freestream nozzle-flow properties.