A non-linear cascade model is proposed to describe the signal transduction pathway in suspension cultures of Taxus chinensis var. mairei induced by an oligosaccharide from Fusarium oxysporum. The oxidative burst intensity, which was defined as the amount of the free radicals including superoxide anion (O-2.), H2O2 and OH- and measured by ESR spectrometry, was used as the signal characteristic and the theory of electronic signal transduction cascade was then applied to derive the initial model. The model shows that the signal transduction cascade process is composed of three cascade nets, represented by the phosphorylation of a G-protein, activation of an ion channel and phospholipase C, and phosphorylation of protein kinase C. The three reactions were calculated as beginning at 30.5, 48.8 and 141.4 min after elicitation, and the maximum variation rates of the signal intensity in the three nets occurred at 43.2, 80.6 and 192.6 min, respectively. The validity of the model predictions was verified by experimental data.