Objective To assess the association of epidermal growth factor receptor (EGFR) mutation with histologic subtypes in lung adenocarcinoma .Methods Lung cancer tissues were collected from 3 028 cases of patients with non‐small cell lung cancer , DNA was extracted respectively ,and EGFR gene exons 18 ,19 ,20 and 2l mutations were dectected by ARMS‐PCR amplification . The association of EGFR mutation with histologic subtypes in lung adenocarcinoma was analyzed .Results The mutation rate of EGFR detection was 39 .7% ,most were exon 19 del and exon 21 L858R (proportion 89 .8% );according to the new classification , EGFR gene mutation in infiltrating lesions with micro infiltrating adenocarcinoma and infiltrating adenocarcinoma were different (P<0 .05) .EGFR mutation rates were higher in moderately differentiated lung adenocarcinoma ,degree of differentiation of EGFR mutation rates were statistically different(P<0 .05) .Conclusion The new classification showes a correlation with molecular diag‐nosis ,different subtypes of EGFR mutation rate is different .There is a certain correlation between EGFR gene mutation and the de‐gree of differentiation in adenocarcinoma .