ObjectiveTo reveal the true value of plasma detection of epidermal growth factor receptor (EGFR) mutation for early-stage non-small cell lung cancer (NSCLC) gene diagnosis and to predict survival prognosis. MethodsTissue samples of positive EGFR mutations by using amplification refractory mutation system (ARMS) method were surgically resected from 198 patients with stage I-IV NSCLC between February 2014 and June 2015 in Tangdu hospital. Paired blood samples were collected before surgery. And the cellfree DNA (cfDNA) in plasma was extracted, plasma EGFR mutations were detected by real-time polymerase chain reaction (PCR). Concentration of cfDNA was measured by ultraviolet spectrophotometry. Follow-up observation for stage ⅢA patients was put into force after surgery. Kaplan-Meire was used in survival analysis. ResultsThe sensitivity of EGFR mutation for the 198 paired tissues and plasma samples was 17.2%.The sensitivity was positively correlated with TNM stage and negatively correlated with tumor differentiation. The sensitivity of sage ⅢA was 33.3%, significantly higher than that of the patients at stage ⅠA (1.6%, P=0.000) and stage ⅠB (7.9%, P=0.004). The sensitivity of poor differentiation was 36.8%, significantly higher than that of high differentiation (0.0%, P=0.000) and moderate differentiation (15.7%, P=0.010). There was no correlation between plasma cfDNA concentration and patient characteristics. Survival analysis showed that plasma detection was a vital factor for predicting postoperative survival prognosis of stage ⅢA patients (P=0.014). ConclusionTissue samples cannot be replaced by plasma samples for epidermal growth factor receptor (EGFR) mutation test in early-stage NSCLC patients, currently. When the sensitivity increases dramatically in the plasma samples of stage ⅢA NSCLC and poor differentiation tumor, we recommend using plasma detection for gene diagnosis, dynamic monitoring of EGFR mutations in stage ⅢA or poorly differentiated tumors, especially in NSCLC patients whose tissue samples cannot be obtained by surgery. And plasma EGFR detection is a valuable method of forecasting survival prognosis for locally advanced NSCLC patients.