Abstract: Based on the study of nonideal flow in gas chromatography column, a model of nonlinear adsorption/partition processes was developed. The model is of probabilistic pattern in ξ-domain, and it can be used successfully to evaluate theoretial plate number required for gas chromatography separation.The experimental results show that the model presented in this work is a general extension of the theory of linear Chromatography. In particularly utilizingm micro-computer, the calculation for predicting column efficiency with a back tail of chromatographic breakthrough Curves can be Carried out rapidly and precisely.