To establish a new method to evaluate the COLD and HOT nature of Coptis & Evodia and their prescriptions Zuojinwan and Fanzuojinwan. Physical models of mice were established by diet restriction with cold-water swimming (weak model, WM) and fed with high protein animal feeds (strong model, SM). An instrument with cold and hot pads was used to investigate the variation of temperature tropism among SM and WM groups of mice affected by drugs. Meanwhile, the oxygen consumption and activity of adenosine triphosphatase (ATPase) were detected, in order to investigate the mechanism of energy metabolism which might be affected by these drugs. The results showed that the drug effects gradually changed in an order of "Coptis-->Zuojinwan--> Fanzuojinwan-->Evodia". In detail, Coptis increased the remaining rate (RR) of mice on hot pad, decreased oxygen consumption and ATPase activity (n=6, P < 0.01 or P < 0.05), while Evodia performed inversely; which indicated the COLD nature of Coptis and HOT nature of Evodia, and confirmed with their traditional definition in medicinal works. In conclusion, the methods applied in this work, can objectively and directly express the nature disparity between the two herbs and predict the tendency of changes of the nature of their combination, which brings a new approach in investigation of the nature theory of traditional Chinese medicine.