A method for digital simulation of unsteady process in melt spinning is described. The method is developed on the basis of methods to solve nonlinear partial differential equations by orthogonal collocation. Computation is illustrated for both steady and unsteady conditions. In the former case the results are compared with those from finite difference method and experimental data.Obtained results are as follows;(1) Good agreement is obtained between the solutions obtained from orthogonal collocation method and those from finite difference method. In the case of steady state, the number of collocation above 12 is needed to get good accuracy.(2) Transient solutions converge very rapidly to one curve for each spinning condition with increasing of number of collocations. And above 12, each solution is closely coincident. Whereas computation time needed is proportional to the square or cube of number of collocations. Therefor we concluded that a numerical model having 12 collocations is usable for simulation of unsteady melt spinning process.