Abstract: By constructing an empirical equation with algebraic form, the key operational parameters of immobilized nitrilaseproducing cells packedbed reactor were determined successfully for nicotinic acid production. A simplified equation, L=7898u cS0+1146u+0028, which describes the relationship of the three key operational parameters (column length L, flow rate u and substrate concentration cS0), was obtained by analyzing the numerical solutions of the established axial dispersion model (onedimension) of packedbed reactor. Under the condition of 3cyanopyridine conversion rate of 95% and the void fraction of 011, the optimal operational parameters of packedbed reactor were obtained by computation based on the algebraic equation for the purpose of maximization of the nicotinic acid production.