The heat shock protein 90α (HSP90α), as a molecular chaperone, plays an important role in the development and progression of various malignant tumors. The aim of the present study was to assess the plasma level of heat shock protein 90α (HSP90α) in patients with non-small cell lung cancer (NSCLC) harboring different epidermal growth factor receptor () mutations and its association with clinical characteristics and gene mutations. Plasma HSP90α levels, clinicopathological data and prognostic information were collected and analyzed from 1,347 patients with a pathological diagnosis of lung cancer to evaluate their association with EGFR gene mutations. The results demonstrated that patients with elevated plasma HSP90α levels are more likely to have SCLC, advanced tumor stages and poorer prognosis compared to patients with lower HSP90α levels. Among patients with NSCLC harboring EGFR mutations, those with higher plasma HSP90α levels are more frequently associated with L858R wild-type and exon 20 mutations compared to other EGFR mutation subtypes. Furthermore, using the optimal cutoff value of 62.1 ng/ml for plasma HSP90α levels, the results revealed that patients with lower plasma HSP90α levels have a better prognosis compared to those with higher HSP90α levels. In conclusion, elevated plasma HSP90α expression is associated with poor overall survival in patients with NSCLC and could serve as a prognostic indicator independent of EGFR mutation status.