The response of central carbon metabolism system of E.coli to environmental changes is a comparatively simple and meaningful model in the interaction between organisms and environment. We have simulated environmental changes with sodium chloride and paraquat. Analyses of key enzymes activities in branch pathways confirmed the response to environmental stress of central carbon metabolism system of E.coli and provided a new visual angle for the regulation mechanism. In 0.2 M NaCl permeability environment, 6-phosphate glucose dehydrogenase/phosphate glucose isomerase revealed significant reduction (~ 69%), the central carbon metabolism flow convert partially from PP pathway to glycolysis pathway. It’s just the opposite with oxidative stress situation. Pyruvate kinase and PEP carboxylase is another important adjustable node. The ratio of pyruvate kinase/PEP carboxylase revealed significant reduction (~ 77%) in permeability environment, which is consistent with the decline trend under oxidative stress.