This study was purposed to evaluate the sensitivity and specificity of G/(1, 3-β-D glucan)/GM (galactomannan) combined detection for early diagnosis of invasive fungal disease (IFD), determine the GM positive cut-off value, and investigate the change of diagnostic level before and after G/GM test and the relation of GM value with therapeutic effect. The ELISA with double antibody sandwich was used to detect the serum levels of G and G/M. The results showed that according to determined GM positive cut-off value, the sensitivity, specificity, positive and negative predictive value of G/GM combined detection were 100%, 65.7%, 67.6% and 100%, respectively. The case number of the clinical diagnosis of IFD increased from 1 to 24 cases, the diagnosis of 12 non-infective patients was changed as suspected IFD with the help of G/GM combined detection; the GM cut-off value decreased in patients whose GM cut-off value was higher before therapy and antifungal therapy was effective, while the GM cut-off value increased in patients no-responded to therapy. It is concluded that G/GM combined detection can increased the sensitivity of the diagnosis and reduce false negative rate in the early diagnosis of IFD. The dynamically monitoring G/GM cut-off value can be used as evaluation indicator of therapeutic efficacy.