Objective To explore the expression levels of ribonucleic acid （miR）-127-5p， miR-127 and miR-155 in elderly patients with pneumonia infection by multidrug-resistant bacteria and their correlation with immune-related cytokines. Methods 65 elderly patients with pneumonia infection by multidrug-resistant bacteria， 80 healthy physical examination persons and 80 elderly patients with common pneumonia in our hospital from June 2020 to June 2022 were retrospectively selected as the observation group， the control group A and the control group B， respectively. The expression levels of miR-127-5p， miR-127， miR-155， interferon-γ （IFN-γ）， interleukin （IL-4）， IL-17， and transforming growth factor-β （TGF-β） in serum samples were detected and compared among the three groups. Pearson correlation analysis analyzed the correlation between miR-127-5p， miR-127， miR-155 and IFN-γ， IL-4， IL-17， TGF-β， and the Receiver operating characteristic curve （ROC） analyzed the diagnostic value of miR-127-5p， miR-127， miR-155 alone or in combination. Results The serum levels of miR-127-5p and IFN-γ in the control group B and the observation group were lower than those in the control group A， and the both in the observation group were lower than the both in the control group B （P < 0.05）. The serum levels of miR-127， miR-155， IL-4， IL-17， and TGF-β in the control group B and observation group were higher than those in the control group A， and those in the observation group were higher than those in the control group B （P < 0.05）. There was a positive correlation between serum miR-127-5p and serum IFN-γ levels （r = 0.463， P < 0.05）， serum miR-127 and IL-4， IL-17 or TGF-β levels （r = 0.306， 0.273 or 0.330， P < 0.05）， and serum miR-155 and IL-4， IL-17 or TGF-β levels （r = 0.410， 0.453 or 0.385， P < 0.05）， and as well as a negative correlation between serum miR-127-5p and IL-4， IL-17 or TGF-β （r = -0.378， -0.396 or -0.408， P < 0.05）， serum miR-127 or miR-155 and IFN-γ levels （r = -0.267 or -0.513， P < 0.05）. Serum miR-127-5p， miR-127 and miR-155 expression levels alone and in combination have a certain diagnostic value in elderly patients with pneumonia infection by multi-drug resistant bacteria， and the area under ROC curve （AUC） values were 0.811， 0.733， 0.817 and 0.906， and the sensitivities were 90.77%， 60.00%， 67.69%， 84.62%， and the specificities were 66.87%， 80.62%， 83.75%， 83.18%. Conclusion MiR-127-5p， miR-127 and miR-155 were differentially expressed in the elderly patients with pneumonia infection by multi-drug resistant bacteria， and were correlated with immune-related cytokines to a certain extent， and the combination of the three has a good diagnostic value， thus may providing a new target for clinical diagnosis of this disease.