【Abstract】Objective This study aimed to evaluate the applicative value of serum galactomannan antigen detection (GM test) in therapy for invasive pulmonary fungal infection. Methods We conducted this singlecenter and retrospective study to examine the characteristics of serum GM test in patients confirmed pulmonary fungal infection by pulmonary phlegm culture. These patients were randomly selected from Department of respiratory and ICU in the Sichuan Provincial People's Hospital. There were 30 patients with Aspergillus infection in the study group, 30 patients with Candida albicans infection in the control group A and 30 patients with no fungal infection in the control group B. We detected the level of serum galactomannan antigen respectively at the beginning(01 weeks), the middle (24 weeks) and the end(46 weeks) of the period of therapy. Then evaluated the applicative value of serum galactomannan antigen detection in therapy for invasive pulmonary fungal infection.Results The results of GM test in patients with effective treatment in the study group before treatment is obviously higher than that after treatment (P= 0.000, t=11.784). However, there was no significance in the results of GM tests upon refractory patients of the study group between before and after treatment(P=0.335, t=0.449). According to the GM test among patients with effective therapy in three groups at the same period of treatment, the results of GM test in the study group were significantly higher than that of the other groups(P<0.05), whereas there was no significant difference about GM test between the control group A and the control group B(P > 0.05). At the end of treatment, there was no significant difference among all the three groups about GM test in patients with effective therapy (P＞0.05).Conclusion Our study revealed that GM test could effectively improve early diagnosis and assessment of prognosis to patients with IPA treatment upon pulmonary invasive aspergillosis. There is great value for further clinical application of GM test.