The relationship between the thyroid functional test in 107 malignant tumour patients' sera with Deficiency-Excessiveness Syndromes in TCM, was studied. The results revealed that there were significant differences between the FT3, FT4 in tumour and control groups (P < 0.01) as well as between the rT3, FT3/rT3 in each type of tumour and control groups (P < 0.05-0.01). There was also definite relationship between the FT3, rT3, FT3/rT3 and the degree of differentiation, rate of progression and malignancy of tumours as well. rT3 elevated and FT3 reduced in accordance with the lowering of body resistance and reinforcing of pathogenic factors. FT3, rT3, FT3/rT3 are essential factors that reflecting the wax and wane of body resistance in the cases with malignant tumours in modern medicine.