It is essential to effectively judge the morbidity of grey model in constructing grey predictive models. Aiming to reveal the change law of modeling parameters of grey Verhulst extended model resulted from a small perturbation of primitive sequence, the spectrum condition number of matrix is taken as a tool of measuring the morbidity of this model, and the values of condition of coefficient matrix with the background value of this model in different case are analyzed. Research result shows that grey Verhulst extended model has no unusually severe morbidity. The research conclusion suggests that, in the grey prediction modeling process, while using the grey extended Verhulst model, the solution of this model will not occur significant drift for the original data series of systems exist minor errors in collecting process.